Embedded Precursor

Step 1: Pull the lever next to the arcade machine. Step 2: Enjoy this blast from the past.

A common bonus feature or Easter Egg in later installments in a Video Game franchise is to hide a copy of an earlier game from the series in the current game.

This is usually (but not always) a hard-to-find special bonus, often an Old Save Bonus or New Game Plus. Additional rewards may be offered for beating the embedded game. For technical reasons, this tends to be limited to games which have a very primitive previous incarnation.

Subtrope of Game Within a Game and as such has to be recreated/emulated by the game itself, it's not the original game bundled with the new one or downloadable for free. See also Nostalgia Level and Compilation Re-release. Has nothing to do with Precursors.

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Video game examples:

A-G

• Age of Empires II: Definitive Edition eventually received the "Return to Rome" Expansion Pack, which for the most part is a port of the content of Age of Empires I: Definitive Edition to the engine of AoEIIDE.
• Alice: Madness Returns includes a high-definition port of the original game as a bonus to players who are willing to pay extra, or those who preordered the game in advance.
• Pre-Order and Day One physical editions of the PS3-version of Assassin's Creed: Revelations include the original Assassin's Creed on the game disc.
• American PlayStation 3 copies of BioShock Infinite include the original BioShock on the same Blu-ray disk.
• Bubble Bobble 4 Friends contains the original game.
• Bullet Hell Monday Black features the five Challenge stages from the original Bullet Hell Monday, but with Black's mechanics.
• The Hardened and Prestige Editions of Modern Warfare 2 include a free redemption code for the Xbox Live Arcade/PlayStation Network port of the first Call of Duty.
• Castlevania:
  • In something of an inversion, Castlevania: Symphony of the Night has the final boss fight from the preceding game as the opening level (although it's referred to as Bloodlines in the English localization). Furthermore, the player's performance in the flashback level determines Alucard's starting stats and items.
  • The Dracula X Chronicles, the PSP remake of Rondo of Blood, contains both Symphony of the Night and the original Rondo of Blood. The former has revised dialogue, rerecorded voice acting and an additional playable character, and the latter is fully translated to the west. Coincidentally, the later Compilation Re-release, Castlevania Requiem, also contains the original Rondo of Blood and the updated Symphony of the Night, but not the remake of Rondo.
  • Castlevania: Legacy of Darkness allows the player to unlock remixed versions of Reinhart's and Carrie's quest from the previous Castlevania game for the Nintendo 64, complete with cut-scenes and everything, but only after completing the main quest with Cornell. However, since Cornell's portion is technically a Mission-Pack Sequel to the first N64 Castlevania, Legacy of Darkness as a whole is really more of an Updated Re-release of the first game than a sequel.
• In Celeste, there's a hidden computer at one point during Chapter 3 that allows you to play the original Pico-8 version of the game. Once found, said game can then be accessed from the main menu later on.
• Final Fantasy Fables: Chocobo's Dungeon: Tokiwasure no Meikyuu features a mini-game with card-based battling... effectively the entire battle/gameplay of its DS predecessor, Chocobo Tales.
• The Chronicles of Riddick: Assault on Dark Athena contains its Xbox predecessor Escape from Butcher Bay with enhanced graphics.
• Centipede (1998): Arcade mode, depending on the release, is either an emulation of the original arcade game, or a recreation of it with Adventure mode's graphics.
• Counter-Strike: Condition Zero, being built on the same engine as the original Counter-Strike, includes all the original maps from that game, alongside some of those same maps recreated for Condition Zero.
• Dariusburst CS Core for the Nintendo Switch has a new stage in CS Mode titled "Darius", which is a retelling of the original Dariusburst for the PSP. The only differences included are the increased enemy count (the original game had fewer enemies onscreen due to the PSP's limited hardware) and the removal of the branching paths and multiple endings.
• Unusually for a current-gen precursor, the entire (slightly-altered) Story Mode of Dissidia Final Fantasy is included in its sequel.
• Cotton Reboot (which despite its title, is a Video Game Remake) also includes the Sharp X68000 version of the original game.
• Contra 4 for the Nintendo DS features the NES versions of Contra and Super C, but they're only available after completing 4 and 8 stages respectively in Challenge Mode. They play almost exactly like the original NES games, right down to having the same cheat codes, except there's no proper 2-Player mode in either game. Instead, both characters are mapped to the same d-pad, but their firing and jumping buttons are mapped differently (Y and B for Player 1, X and A for Player 2).
• The Day One Edition of Dark Souls III on Xbox One includes a digital copy of Dark Souls, playable via the Xbox One's backwards compatibility mode.
• Day of the Tentacle was the sequel to Maniac Mansion and has a fully playable version of it on Ed's 64K computer (implied to be the C64). Just like the original version, it only has one save slot. This also applies to the HD version, where you also get some achievements for trying it out and microwaving the hamster. Multiple save slots were added in a patch.
• DanceDanceRevolution:
  • The arcade version of 3rdMIX has a hidden "2ndMIX" mode that allows you to play songs from the first two games, with the exception of "Strictly Business". And much thankfully, with 3rdMIX's difficulty selection method so you don't have to enter a code for Another or Maniac difficulties.
  • 2ndMIX gets revisited as a separate mode again in X3 vs. 2ndMIX, this time as an HD remaster. It isn't a perfect recreation, though; some of the features from the original are missing, "Strictly Business" is absent once again, it uses the X cut of "Hero" instead of the original one, and two new boss songs are added.
• Dead Space 2 Limited Edition on PlayStation 3 included the HD remastered version of Dead Space: Extraction (being a prequel to the first game), complete with move support, and an additional difficulty level.
• This is fairly common in the Doom series:
  • Doom³ Collector's Edition for the Xbox included PC-perfect ports of Ultimate Doom and Doom II, complete with four-player split-screen multiplayer. All copies of its standalone Expansion Pack Doom 3: Resurrection of Evil also include the first two games, plus the Master Levels of Doom 2.
  • There is also Doom 3 BFG Edition, which includes the first two Doom games. The Xbox 360 and PS3 versions play much the same as their downloaded counterparts, while the PC version uses the original wad files, plays like how it did when it was initially released (sadly with no multiplayer support), and also includes the campaign "No Rest for the Living". Thankfully, you can still extract the wad files and use it in various source ports to make up for the lack of multiplayer, and more. Later on, the Steam release bundled the BFG Edition with the original Doom 3, requiring users to buy the former to get the latter but in turn automatically upgrading anyone who had either version to owning both.
  • Doom Eternal contains an in-game PC with fully-playable (if slightly dodgy) versions of both Doom and Doom II, meaning that, yes; now even DOOM can run DOOM. Both have to be unlocked - Doom is unlocked by collecting all 14 floppy disks, and Doom II is unlocked by entering the passcode FLYNNTAGGART. Pre-orders of the game also came bundled with a port of Doom 64.
• Donkey Kong:
  • Donkey Kong '94 starts with all four levels from the original Donkey Kong arcade game. Stage 9-4 is a remake of the final stage from Donkey Kong Junior, while Stage 9-5 is an updated version of the very first stage balanced out for the game's new play mechanics.
  • Donkey Kong 64 features working arcade machines on which the player can play the original Donkey Kong and Jetpac (Rare's first game back when they were named "Ultimate Play the Game") to win a reward token. These tokens are actually necessary to access the final boss.
  • One of the racetracks from Diddy Kong Racing (Greenwood Village) can be unlocked for multiplayer mode in Jet Force Gemini after completing both tracks (broken time records included) from Jeff and Barry Racing (itself, funnily enough, a Game Within a Game).
• Parodied with Duke Nukem 3D. The first level has an arcade cabinet that runs Duke Nukem II. Interacting with it simply has Duke say "Hmmm, don't have time to play with myself." This is played straight for the DOS versions released at retail. When installing the game, you have the option to install demos to other DOS games, as well as all episodes to Duke Nukem, and Duke Nukem II. It does get parodied again with Duke Nukem Forever, where the first level is a recreation of the final stage of Duke Nukem 3D
• The Japanese version of Dragon Ball: Origins 2 contains the first Dragon Ball Famicom game, Dragon Ball: Shenron no Nazo (which was stripped of the Dragon Ball license for its English release as Dragon Power).
• In Dynasty Warriors 7, the entire game of Dynasty Warriors 2 was available as DLC with the updated character roster for its 10th anniversary.
• EA Sports will tend to include a classic iteration of a sports game; Madden 2002 included Madden '92, FIFA 06 included FIFA International Soccer, and NHL 06 included NHL '94 (due to licensing issues, all the older versions contained modern rosters instead of their original ones).
• The Sega Saturn version of Elevator Action Returns contains the original game as a bonus.
• The Xbox 360 version of Eschatos includes its spiritual predecessor Judgement Silversword and the Gaiden Game Cardinal Sins on disc.
• EZ2DJ 6th Trax has a mode called "Remember 1st?", which literally closes the game and launches an executable for 1st Tracks that is also on the game's hard drive (to the point you can even see the empty Windows 98 desktop for a moment in between).
• The Nintendo GameCube version of Fight Night: Round 2 includes Super Punch-Out!!.
• Final Fight: Streetwise contains the unlockable Final Fight arcade game. Unfortunately, they didn't get the sound and controls right.
• Fire Emblem: Mystery of the Emblem had this in a sense. It contained both a remake of the first and its sequel, though both were available from the beginning. In turn, its remake New Mystery of the Emblem contains remakes of the obscure BS Fire Emblem: Akaneia Saga Satellaview games as unlockable bonuses.
• Fist of the North Star: Lost Paradise has a Master System that survived the nuclear apocalypse with a copy of Fist of the North Star, which had been released overseas as Black Belt.

G-O

• A minor example in Ghostbusters: The Video Game—in the Firehouse, a monitor with the infamous victory screen from the infamous Ghostbusters (1984), released on the NES and Atari 2600, can be found.
  Conglaturation !!! You have compelted a great game. And prooved the justice of our culture. Now go and rest our heroes !
• Giana Sisters DS has every level from the original The Great Giana Sisters as an unlockable.
• While FiveM is a Game Mod for Grand Theft Auto V, its menu displays the Grand Theft Auto III version of Liberty City in the background, and an "Into the Game!!!" button on its main menu lets you play III. Actually getting to explore the low-poly Liberty City was initially just an Easter Egg, but a later version made it a normal menu option.
• Hitman:
  • Hitman 2 has two DLC "Legacy packs" that add missions, challenge packs, Elusive Targets, and certain escalations from Hitman (2016) into the game (The first DLC being the Base game and Bonus Episodes, and the second DLC adds upon this with also including the Patient Zero campaign and other things part of the Game of The Year Edition), all of which have been updated to include the new features found in Hitman 2 (such as Stealth Grass and mirrors working like mirrors). Owners of Hitman (2016) can get either of the DLC's for free, depending on purchase history. It's also notable because this Embedded Precursor will effectively double the entire game's filesize (from about 70GB to 155GB!).
  • Hitman 3 includes all of 2016 (including all the GOTY Content), and all but the Gold Edition content (two levels, sniper assassin, special assignments) from Hitman 2. And, in an inversion of Hitman 2, the total file size of the game has shrunken down to about 67GB, almost 1/3rd of the total Hitman 2 size and only nominally bigger than 2016 was.
• House of the Dead 3 for the Xbox contains the full version of House of the Dead 2. Incidentally, much later came House of the Dead 2 & 3 Return on the Wii. The Dreamcast version of House of the Dead 2 was supposed to include an Enhanced Remake of the original title, but it wasn't implemented due to time constraints, instead a short summary with scenes of the first game rendered in the second game engine was featured in the console version Attract Mode.
• The Wii version of Indiana Jones and the Staff of Kings includes the PC game Indiana Jones and the Fate of Atlantis (voiced version).
• Instant Brain is a Xbox 360 Visual Novel published by Cave that includes a port of the original DoDonPachi. The port also includes Kinect support.
• Kingdom Hearts II: Final Mix+ includes a remade midquel given almost equal billing to the game itself, Re: Chain of Memories, which takes the GBA sprite game and turns it into a full-fledged 3D PS2 game. However, that is a standalone release in America (and thus merely a remake), with Final Mix+ itself taking its sweet time coming overseas in the form of Kingdom Hearts HD 2.5 (containing a console port of Birth by Sleep due to the remake of the first game having Re: Chain of Memories).
• The King of Fighters: '94: Re-Bout, '98: Ultimate Match and 2002: Unlimited Match all have the original Neo Geo AES versions they were remade from included, although only in the PS2 version in 2K2UM's case.
• Kirby Super Star:
  • The first game that you're allowed to play, Spring Breeze, is actually a condensed remake of the first game in the Kirby series, Kirby's Dream Land. Emphasis on "condensed"; it most notably lacks Castle Lololo and Kaboola.
  • Kirby Super Star Ultra not only has Spring Breeze, but also Revenge of the King; the latter is a remake of Dream Land's Extra Game (essentially Hard mode), and unlike Spring Breeze, it does include Kaboola.
• The 2023 version of Layers of Fear lets you replay both the two previous games and the DLC for the first game, the premise is that the main character of the new game is a writer and the previous games were her books which you can read and replay.
• Left 4 Dead 2 now contains ports of all the campaigns from the first Left 4 Dead, including an expanded version of the Survival-only campaign "The Last Stand" that now supports all game modes.
• LEGO Dimensions, via the Midway arcade level pack, contains emulated ports of twenty-three Midway arcade games.
• The PlayStation Portable version of LEGO Star Wars II: The Original Trilogy features the final levels of each episode of LEGO Star Wars: The Video Game as bonus levels.
• The remake of Makai Toushi Saga on the WonderSwan contains the original Game Boy version, which was released in the US as The Final Fantasy Legend.
• Mario Kart:
  • Mario Kart: Super Circuit has all the courses from the original as an unlockable, albeit rearranged from the original's four cups of five into five cups of four.
  • All the games beginning with Mario Kart DS began to feature 32 tracks. These tracks were divided into four "Nitro" Cups (containing all-new tracks), and four "Retro" cups (containing old tracks from previous Mario Karts). While there are 16 retro tracks per edition, how many are from each previous edition differs:
    • As the fifth installment in the series, DS has four tracks each from Super Mario Kart, Mario Kart 64, Mario Kart: Super Circuit, and Mario Kart: Double Dash!!.
    • Mario Kart Wii brings back two courses each from Super Mario Kart and Mario Kart: Super Circuit, and four each from Mario Kart 64, Mario Kart: Double Dash!!, and Mario Kart DS. Many of the courses are modified to make use of the new Trick ability.
    • The retro cups in Mario Kart 7 bring one course from Mario Kart: Super Circuit, two courses each from Super Mario Kart and Mario Kart: Double Dash!!, three from Mario Kart 64, and four each from Mario Kart DS and Mario Kart Wii. Almost all of the retro courses have been modified in some way to incorporate the new underwater driving and/or hang gliding mechanics.
    • In the base game, Mario Kart 8 has 16 retro tracks: one track each from Super Mario Kart and Mario Kart: Super Circuit, two each from Mario Kart: Double Dash!! and Mario Kart Wii, three each from Mario Kart DS and Mario Kart 7, and four from Mario Kart 64,. As with the retro tracks from 7, those in this game feature altered sections that incorporate the game's hang-glider, underwater, and anti-gravity features. The DLC packages add an additional seven retro tracks (one track each from Super Mario Kart, Mario Kart Wii, and Mario Kart 7, and two each from Mario Kart: Super Circuit and Mario Kart: Double Dash!!) and nine new ones, all of which are included by default in Mario Kart 8 Deluxe. The Booster Course Pass DLC adds an additional 48 courses, which include two tracks each from Super and 64, three from Double Dash, four each from DS and 7, five from Super Circuit, eight from Wii, 17 from Mario Kart Tour, and 3 all new tracks^note Courses Ninja Hideaway, Merry Mountain, and Piranha Plant Cove all debuted in Tour prior to launching in the Booster Course Pass despite lacking the label for Tour.
• A subversion of this trope: Mass Effect 2 for the PS3 was released before the Mass Effect Trilogy, and as such, there was no PS3 port of Mass Effect 1 at the time. To make up for this, BioWare included an interactive comic book that summarizes the events of the first game and allows the player to make decisions on important events to determine how some set pieces are arranged.
• Mary Skelter 2 includes an enhanced remake of Mary Skelter: Nightmares. In-Universe, however, the remake continues from the sequel's Reset Button Ending and allows the couple who pressed said Reset Button to finally earn a happy ending.
• The PS3 version of Medal of Honor (2010) contains a remastered version of Medal of Honor: Frontline, with optional modern controls and iron sights.
• The 2019 PS4 remake of MediEvil adds a side quest late in the game not found in the 1998 version, involving collecting Lost Souls and revisiting the levels to lay them to rest. Completing the quest and going back to the main menu unlocks the original game, fully playable.
• Metal Gear:
  • The second disc of Metal Gear Solid 3: Subsistence includes updated versions of the original Metal Gear and Metal Gear 2: Solid Snake, which were originally released for the MSX2 and never released outside Japan in their original form before then (only the first game had an infamous NES port). Both games are included in the HD Edition of MGS3 released for the PS3, Xbox 360 and Vita, where they're selectable via the main menu.
  • The Metal Gear Solid 2: Digital Graphic Novel DVD in Japan includes a fully voiced version of the original Digital Graphic Novel that was released for the PSP.
  • Metal Gear Solid 4: Guns of the Patriots has a scene where Old Snake is sleeping while on the way to revisiting Shadow Moses Island, and in his dream you can play a perfect emulation of the opening Heliport from the first Metal Gear Solid.
• One of the bonuses for connecting Metroid Prime to Metroid Fusion was a playable copy of the original Metroid. And after beating Metroid: Zero Mission once, the original Metroid was unlocked on the options menu.
• The 40th Anniversary update of Microsoft Flight Simulator includes the first four versions of the game^note Microsoft Flight Simulator, Microsoft Flight Simulator 2, Microsoft Flight Simulator 3 and Microsoft Flight Simulator 4.0 fully playable, accessible after loading up a DA62 in cockpit view and setting the ELT to the on position.
• The Premium Pack/Kollector's Edition of Mortal Kombat: Deception has the original Mortal Kombat, Mortal Kombat: Shaolin Monks has Mortal Kombat II as an unlockable (relevant as Shaolin Monks is essentially a retelling of MK2), and looking at the pattern, you can tell what the Limited Edition of Mortal Kombat: Armageddon includes.
• The Super Mario World ROM Hack The New 5 Difficult Bosses by Daizo dee Von includes all of its predecessor, The 5 Difficalt bosses in a bonus level.
• Night Trap 25th Anniversary plays with this by including Scene of the Crime, a prototype game that was never released but is essentially the precursor to Night Trap itself.
• The Xbox version of Ninja Gaiden features the three NES games in the franchise (although they're based on the updated versions from the Ninja Gaiden Trilogy compilation for the SNES and not on the actual NES originals). To play them, you need to find their corresponding cartridges and use them with an arcade cabinet in Tairon. If you beat the game after finding the cartridges, you can play them from the main menu. The expanded version, Ninja Gaiden Black, replaces them in favor of the 1988 arcade game.
• A visual novel example, Narcissu is added as an embedded package to its prequel, called "Narcissu ~Side 2nd~".
• The Video Game Remake of Odin Sphere, Odin Sphere Leifthrasir, features the original Odin Sphere in its entirety as an alternate game mode that can be swapped to through the title screen.

P-Z

• Pac-Man:
  • Pac-Man 2: The New Adventures for the SNES has an arcade where you can play the original Pac-Man. If the player collects all three pieces of a Game Pack, they can also unlock Ms. Pac-Man. The Genesis version had an original game, Pac-Jr. (not to be confused with Midway's Jr. Pac-Man arcade game), in lieu of Ms. Pac-Man (since Ms. Pac-Man already had a standalone release for the Genesis).
  • The main menus for Pac-Man World and Ms. Pac-Man Maze Madness have a "Classic" option, which allows you to play a version of the original Pac-Man and Ms. Pac-Man, respectively. Pac-Man World Re-Pac also features the original arcade game, though this time it has to be unlocked first by clearing the main game.
  • In Pac-Man World 2, if Pac-Man collects enough arcade tokens throughout the game, the player can unlock various classic Pac-Man games. 10 tokens unlocks Pac-Man, 30 unlocks Pac-Attack, 100 unlocks Pac-Mania, and 180 unlocks Ms. Pac-Man.
  • In the Nintendo DS version of Pac 'n Roll, Stage 7-1 is actually the original Pac-Man arcade game as a playable minigame.
  • Pac-Man Party includes the original Pac-Man as a playable game in the menu, though Galaga and Dig Dug are thrown in as well, both games receiving minor nods within the main game.
• Panzer Dragoon Orta, the fourth game, contains an unlockable port of the first.
• The Persona: Dancing Endless Night collection on PS4 is a bundle that contains not only Persona 3: Dancing in Moonlight and Persona 5: Dancing in Starlight, but also an exclusive PS4 port of Persona 4: Dancing All Night, previously released on the Vita. The catch is that this game can't be bought separately, only part of this bundle.
• All nine of the levels from PAYDAY: The Heist have been remade for PAYDAY 2, with additions and changes to accommodate the gameplay mechanics of Payday 2. Seven were added in free updates for all players, those being First World Bank, Slaughterhouse, Panic Room, Heat Street, Green Bridge, Diamond Heist, and No Mercy, while Undercover and Counterfeit, mirroring how they were released for the first game, were included with a new version of the "Wolf Pack" DLC for Payday 2. Of all these heists, only First World Bank and Diamond Heist can be played fully in stealth (the latter allowing you to complete the entire heist in stealth, whereas the original game required you to go loud eventually), while the Wolf Pack heists can only be done in stealth up to a point. Some of these heists, most notably Heat Street, have also been recontextualized to better fit PAYDAY 2's story—except for No Mercy, which plays exactly as it did in the first game (minus enemy spawns). This also has a lore justification, as the virus that is killing Bain is similar to the one the Gang obtained from Mercy Hospital, and what you're actually playing is a flashback to that event.
• The Cook Off and Murky Station heists from PAYDAY 2 are also playable in PAYDAY 3. They've been modified from the original game to better fit the mechanics of PAYDAY 3.
• Pitfall!: Mayan Adventure has a hidden copy of the original Pitfall hidden inside it. So does Pitfall 3D: Beyond the Jungle, via a password, and Pitfall: The Lost Expedition. The Big Adventure, a remake of The Lost Expedition, takes it one step further by having both the original Atari 2600 Pitfall games as unlockables.
• Prince of Persia: The Sands of Time included the original Prince of Persia as a bonus. It was reached by opening a hidden door, walking up a staircase, and passing out of view. The dialogue sets it up just prior: "They say this castle was built on the ruins of an even more ancient one..." The Xbox version also included Prince of Persia 2.
• Super Nazo Puyo: Rulue no Roux has two main scenarios, one of which is a remake of Nazo Puyo: Arle no Roux.
• Quake 4 Special Edition for PC included a second disc that includes Quake II and all its expansions. Xbox 360 owners have a similar deal: A faithful 360 port of Quake II, playing exactly like its PC counterpart, with the added bonus of four-player split-screen, plus up to 16 players via a local area network. The only downsides are no expansions are included, no auto-aim, and no online play.
• Radirgy 2 includes a port of the first game that is also playable on PlayStation 4/5 and Switch.
• The Xbox One version of Rainbow Six Siege includes the 360 versions of Rainbow Six Vegas 1 & 2, fully playable on the Xbox One.
• Rayman Legends contains levels from its precursor, Rayman Origins that you unlock by collecting Lucky Tickets.
• Ridge Racer Type 4 came with a bonus disc that includes both the original Ridge Racer and a stripped-down version of Ridge Racer enhanced to run at 60fps. (As opposed to both the original version of the game and Type 4 itself, which both run at 30fps.) According to an "Information" option on the main menu, the devs aimed to get Type 4 running at 60fps but deemed the compromises necessary to be too much. Not wanting the effort needed to get it working to go to waste, they bundled in the demo they were testing with as a bonus.
• Rod Land. In the arcade version, inputting a code on the title screen once you put a coin in unlocks a sequel that never saw a standalone release.
• The 1990s PC version of Space Invaders lets you play the original Space Invaders once you've beaten the game on Hard.
• The 2010 version of Splatterhouse includes the original arcade game and both Genesis sequels.
• Sonic the Hedgehog:
  • Sonic Adventure DX for the Nintendo GameCube and PC has every single Sonic Game Gear game released, from the original 8-bit Sonic the Hedgehog (acquired by collecting 20 Emblems) to Sonic Blast and Tails Adventure (acquired by getting all Emblems and completing Mission Mode). Because of this comprehensiveness, this marks the first time Sega officially distributed Sonic Drift and Tails Skypatrol outside of Japan.
  • Sonic Generations includes a port of the original 16-bit Sonic the Hedgehog as a bonus, but only in the console version (since the game is already available separately on Steam and Nintendo 3DS).
  • Sonic the Hedgehog Megamix is a Game Mod of Sonic 1 that not only remixes all of its zones, but also has their original versions kept intact with the bonus of being about to go through them using the hack's new characters, controls, and physics.
• The fangame Sonic Robo Blast 2 included all the levels of the original Sonic Robo Blast running on the SRB2 engine (including all the 2½D that comes with it) as an unlockable bonus in versions 2.0 and 2.1 (beforehand available as a standalone pack for 1.09.4). It has since been removed in 2.2, though a new add-on pack is available here.
• Spark the Electric Jester 3 features all of Spark the Electric Jester 2's levels as Downloadable Content.
• The Xbox version of the 2001 SpyHunter game includes the original Spy Hunter.
• Star Fox: Assault: By collecting all of the silver medals in the game, players can unlock the NES port of Namco's hit arcade shooter Xevious as a bonus feature. The Japanese version even features 2 extra Namco games. Battle City and Star Luster, as well.
• A minor selling point for Star Wars Rogue Squadron III: Rebel Strike (it was mentioned on the back of the box) was the fact that an almost complete version (minus the Empire-based bonus missions) of the previous game, Rogue Leader, was available for co-op play. The game also includes ports of the Atari arcade games Star Wars, The Empire Strikes Back and Return of the Jedi, which can be earned through game play and/or by pass code.
• The PS3 version of Stranglehold contains a HD remaster of the film Hard Boiled, which the game is a sequel to.
• Super Famicom Wars has all the maps from the original Famicom Wars in addition to all the new ones made for the game.
• Super Mario Bros.:
  • In Super Mario Bros. 3, players collect cards at the end of most levels. In a two-player game, if one player is on the same square in the map as the other player, either player can press a button to enter a fight. This fight is played as a round of a slightly modified version of the original Mario Bros.. The player can steal cards from the other player to earn 1-UPs, and the winner gets to go to the next level. Super Mario All-Stars also includes said battle mode as a separate mode on the title screen of SMB3.
  • Every Super Mario Advance game, as well as Mario & Luigi: Superstar Saga, also included a remake of Mario Bros.. And you can link two GBA for multiplayer too, even if you're not using the same game that has it! ^note i.e. You can use a copy of Super Mario Advance 3 and Mario & Luigi: Superstar Saga to play a multiplayer round of Mario Bros.
  • Super Mario 3D World features a slightly tweaked version of the original arcade game called Luigi Bros. (meant to cap off a marketing campaign known as The Year of Luigi). It's unlocked by beating the game or having a New Super Luigi U save game on your Wii U. ^note For the Switch version, the game can only unlocked by beating the game; having a New Super Luigi U save file through New Super Mario Bros. U Deluxe does not unlock it.
  • WarioWare, Inc.: Mega Microgame$: Unlike all the standard microgames based on classic Nintendo games (which only replicate very small portions of their games of origin), three of the special minigames unlockable by scoring high enough in Jimmy T.'s chapters are full-fledged adaptations of games: Dr. Mario, Sheriff, and the Fly Swatter minigame from Mario Paint. The main difference in the former two is that they're starred by Wario instead of Mario and the nameless Sheriff respectively.
• The Super Monkey Ball 2 ROM Hack Monkeyed Ball 2 contains most of the story mode of Monkeyed Ball 1 with updated textures and custom music in Worlds 1 and 3.
• Super Smash Bros.:
  • The series tends to feature stages from previous entries in each new game, with Super Smash Bros. Melee featuring three stages from the original N64 game, Super Smash Bros. Brawl featuring ten stages from Melee, Super Smash Bros. for Nintendo 3DS featuring three stages from Melee and five stages from Brawl (along with three stages from the original game as DLC), and Super Smash Bros. for Wii U featuring 14 stages from Brawl (13 already included and one as DLC), 3 stages from Melee, and four stages from the original game (one already included and three as DLC). Brought to its logical extension in Super Smash Bros. Ultimate, which features almost every stage that has ever been in the series (the only ones missing are two stages from the original game, four stages from Melee, two stages from Brawl, two stages from the 3DS game, four stages from the Wii U base game, and one stage from the DLC).
  • Brawl and Wii U also feature the ability to unlock several games from the various video game franchises represented. These are all timed demos, though, due to the existence of the Virtual Console, though frustratingly, not all demos were on the VC. With a little bit of modding, it is possible to play these games not as timed demos, but as full games.
• Tales of Phantasia: Narikiri Dungeon X (PSP) features (an updated version of) Tales of Phantasia in the same UMD.
• TMNT2: Battle Nexus and TMNT3: Mutant Nightmare include ports of the original arcade game and Turtles in Time, respectively. The latter, sadly, does not have some of the original music and voices due to legal issues.
• Tekken:
  • The first game had an embedded Galaga. If you want to unlock Devil Kazuya, you have to clear eight stages of it.
  • Tekken 5 included fully-playable Arcade versions of the first three Tekken games. You can also unlock the full version of Namco's old space shooter Starblade by finding the spaceship from that game in one of the stages of Devil Within. Usually you get to play the first part of the game when Tekken 5 itself is starting up.
• Tetris Worlds contained a re-creation of the original Tetris, prior to the Executive Meddling that introduced infinite spin and T-spin triples, complete with monochrome blocks made out of bracket characters.
• The Japanese version of 13 Sentinels: Aegis Rim includes a download code for a HD remaster of Princess Crown (Vanillaware's first game) as a pre-order bonus.
• Time Crisis Razing Storm for the PlayStation 3 boasts that it includes the arcade version of Time Crisis 4, which is essentially the same game as its individual release, only with Playstation Move support, and the complete story mode completely absent (not that many people minded). Dead Storm Pirates (which isn't a precursor) was also thrown in for good measure.
• Played with in Tony Hawk's Underground. After creating a character, you can briefly see the game box for Tony Hawk's Pro Skater 4 on the desk. Played straight in the Xbox version of Tony Hawk's Pro Skater 2, which includes all of the levels from the original game plus their original campaigns as bonus levels, essentially allowing one to play the first game using the Pro Skater 2 engine.
• Tron 2.0: Killer App for the Game Boy Advance incorporates the old TRON arcade games by Midway.
• Uncharted 4: A Thief's End has a segment in which Nate plays through the Boulders level of the first Crash Bandicoot.
• White Knight Chronicles 2 came with the predecessor as well, updated to reflect the changed (read: better) combat system.
• Wolfenstein:
  • The PC version Return to Castle Wolfenstein contains Wolfenstein 3-D on the disc as a separate game. It is an unlockable in the Xbox version.
  • In the levels taking place at Kresiau Circle HQ, if you sleep on the matress upstairs your can play the first level of Wolf3D in Wolfenstein: The New Order.
  • Wolfenstein: The Old Blood expands on the trend started in The New Order, with a mattress somewhere in each level accessing a corresponding level of the first episode of Wolfenstein 3-D, up to and including the first episode's end boss fight against Hans Grosse.
  • Wolfenstein II: The New Colossus features the entirety of Wolfenstein 3D as an arcade game called "Wolfstone 3D". In a twist, it stars a Nazi hero with the bosses replaced by pixelized caricature of the heroes. The Nazi imagery was replaced by the Resistance imagery as well.
• Wrecking Crew '98 for the Super Famicom includes the original NES game.

Non-video game examples:

• Tabletop Games example: the Dungeons & Dragons boxed set Return to the Tomb of Horrors had a copy of the original module S1 Tomb of Horrors included in it. The original Tomb was placed within the larger adventure and could be entered and explored.
• Many computer and video game console formats use this as a method of achieving backwards compatibility. Sometimes the hardware simply has a special compatibility mode that it uses to run older software, and sometimes the older system's hardware is entirely separate from the new hardware. The latter approach can be costly, since including an entirely separate system, even an older one, can increase the cost of manufacturing the hardware significantly, which is why certain systems omit backwards compatibility.
• The Commodore 128 turned itself into a Commodore 64 if you typed "Go 64." The ZX Spectrum did the same thing (the +2 had a 48K mode, selectable from the startup menu) for the exact same purpose: backwards compatibility. In the case of the 128, it resulted in the amount of 128 specific software remaining quite low, as many developers preferred to target the wider audience of Commodore 64 users.
• Sega consoles:
  • Games from the SG-1000 can be played on the Mark III natively, as the Mark III was built on the same hardware and contains the SG-1000's BIOS. Internal changes were made when the Mark III was released internationally as the Master System, meaning it lost this compatibility.
  • The Sega Genesis contains all of the Sega Master System's hardware within it; it only needs an adaptor cartridge to run Master System games because its carts are a different shape. The Master System's Z80 processor is actually critical to the Genesis, as it handles all of its audio output.
  • The Sega Saturn was apparently to have an embedded Sega Genesis and 32X in it at one point (judging from the presence of a M68K CPU), but the idea was scrapped very early in development as a Z80 was not included in the final system and the final product does not have the backwards compatibility.
• PlayStation system:
  • The PlayStation 2 actually had a MIPS R3000, the processor of the PlayStation, installed as a co-processor, as a result it had backwards compatibility with PS1 games.
  • The Early PlayStation 3 consoles actually take things up a notch by having both the R4000 and R3000 CPUs, as well as the Emotion Engine, present as co-processors for the Cell CPU (the R3000 was repurposed as an I/O co-processor with the option of taking over when a PS1 game is inserted, while the R4000 was present solely for backwards compatibility. Sadly, later PS3 models dropped the R4000 to cut costs.
  • The Play Station Vita has most of the PlayStation Portable's hardware consolidated onto a system-on-a-chip, which is how it is backwards compatible with PSP games.
• Nintendo systems
  • Subverted with the Super Nintendo Entertainment System. Like the Sega Saturn, there's evidence based on its hardware that Nintendo initially planned to make the system backwards compatible with NES games, since the CPU is an enhanced 16-bit version of the MOS Technology 6502 processor used in the older console, the PPU contains modes that are compatible with NES graphics, and the controller interface is similar, but ultimately Nintendo didn't go through with it.
  • The Game Boy Advance contains a Zilog Z80 CPU as its sound processor, which is the same CPU used in the Game Boy and Game Boy Color and allows the Advance to have backwards compatibility with those systems.
  • The Nintendo DS has 2 CPUs, one of which is an ARM7 CPU like the Game Boy Advance used, which it uses to run GBA games. The DS' ARM7 runs at 33 MHz as opposed to the GBA's 16 MHz, which requires the DS' processor to run at half speed when running a GBA game.
  • The Nintendo 3DS contains the Nintendo DS' hardware for backwards compatibility, including the GBA hardware; however since the 3DS lacks a GBA cartridge slot, the GBA compatibility was only used for 10 downloadable GBA games that were made available to early adopters of the system to who purchased it prior to a price drop.
  • The Wii used hardware that was very similar to the GameCube's, only running at faster speeds, which is how it was able to be backwards compatible with its predecessor. The Wii U uses a multi-core version of the same CPU, but has a vastly different GPU, and is backwards compatible with Wii games thanks to having a Wii GPU embedded into it. Though it isn't officially compatible with GameCube games, hackers have gotten them to work on the console.
• A strange example that skips a generation: The Xbox One actually has an evolution of all the components found in the original Xbox (the AMD CPU is an evolution of the Intel Pentium III found in the Xbox and supported the full ISA, and GPU did not matter given that it was abstracted by means of the DirectX API), making it more than capable of running original Xbox titles. Software-wise, the system uses a newer version of the DirectX API compared to its predecessor and the Windows 10-derived kernel is an evolution of the Windows 2000-derived kernel that its predecessor uses. However, compatibility with games of the precursor console took several years to surface on the machine.
• Leonard Bernstein wrote a sequel to Trouble in Tahiti, the full-length opera A Quiet Place, which in the end included all seven scenes of Trouble in Tahiti as a pair of Pensieve Flashbacks in the second act.
• The Brazilian publisher of Disney comics released a collection to celebrate the 60th anniversary of their Donald Duck comic. A fac-simile of The Donald Duck #1 (yes, the first issues had an article) came along with the first issue.
• The DVD releases of Most Extreme Elimination Challenge include a few unedited original episodes of Takeshi's Castle which is longer than the show's edit that puts the show into its proper context. The catch is however that the English subtitles are burned to the image. It also has an optional English announcer (but only for the first season, that option's been removed for Season 2, Volume 3, and the Volume 4 and 5 two-pack.).
• The DVD for House of Wax (1953) includes the film it was a remake of, Mystery of the Wax Museum (1933) as a bonus feature.
• The mid-2000s anime The Tower of Druaga based on the 1984 NES Video Game The Tower of Druaga has an episode where the party, while climbing the titular tower, arrive on a floor which contains the original tower from the 1984 Video Game. When the main character enters it the other characters are able to use a nearby control console together with a Guide Dang It! obtained from a nearby shop to 'body control' him through the very trials from the video game, even inserting coins into the console and respawning him on level 1 of the tower each time he died, just like the very Guide Dang It! game.
• Selected Baen Books hardbacks include a CD which often contains the earlier books in the series.
• When automatic couplers were introduced on British commuter trains in the 1950s, they were of a design that incorporated a hidden old-style screw coupler, so that in an emergency the unit could be towed by a steam or diesel locomotive.
• The two-disc DVD of the 1960 version of The Lost World includes the 1925 version which the later film is a remake of as a bonus feature. Ironically, the release is generally more sought-after because it has the 1925 film in fairly good quality and not because of the 1960 film, which is advertised as though it's the main attraction.
• Some releases of the special editions of the original Star Wars trilogy include the original theatrical versions as bonus features. These discs are in high demand because of the theatrical versions, although they're presented in very low quality compared to the special editions.
• Metallica: All of the tracks from their 1987 all-cover $5.98 EP, as well as the original "Garage Days Revisited" (released in Europe as a B-side to the "Creeping Death" single), were included on the second disc of Garage, Inc., which is a Distinct Double Cover Album.
• The Ultimate Collector's Edition of Van Helsing included the original Universal Horror films most directly inspirational of the film — Dracula (1931), Frankenstein (1931), and The Wolf Man (1941).
• As expected, many of the 9th generation of home consoles are basically evolutions of their 8th generation counterparts, running off the same ISA and having similar hardware. For example, the PlayStation 5's Zen-2 based CPU and RDNA2 GPU are basically evolutions of the Jaguar CPU and Southern Islands GPU respectively, ditto for the Xbox Series X|S consoles. Aside from some changes to the console's layout, the PlayStation 5 can natively run PlayStation 4 games without emulation or virtualization. The same is true for the Xbox Series consoles being able to run Xbox One games natively.
• Early versions of Mac OS X contained a copy of Mac OS 9 that could be run via virtualization to support older software that hadn't been ported to OS X yet.
• IBM Personal Computer:
  • Modern PCs still have many legacy technologies and hardware such as ISA built-into them, even if they don't have any means of actually using those features. With the correct BIOS settings, it's actually still possible to boot older OS's like MS-DOS, although doing anything meaningful once you've booted is another matter^note one legit reason to still do this is to update the GPU BIOS, or force a user-modified UEFI BIOS that the built-in flasher rejects.
  • 32-bit x86 CPUs contain something called Virtual 8086 Mode which virtualizes the 8086 processor, the very first x86 chip, allowing 16-bit real mode applications to run in a multi-tasking environment. It's not available when running in 64-bit mode, however, which is why 64-bit Windows cannot run 16-bit apps. In what may be yet another example of this trope, 64-bit CPUs can run 32-bit operating systems in a compatibility mode where it can still be accessed. This has also resulted in a fork of WINE that basically acts as a translation layer that converts 16-bit calls to newer 32-bit calls so the program can continue to run on Windows' compatibility mode.
  • 32-bit versions of Windows NT included a DOS installation that could be run via the aforementioned Virtual 8086 mode in order to run DOS and 16-bit Windows apps.
  • Windows 7 contained a "Windows XP mode" which enabled apps to run exactly as they did on Windows XP, avoiding any and all compatibility issues they may have with 7. This utilized a full blown, virtualized instance of Windows XP, similar to the Classic Environment on early versions of Mac OS X.

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