In quite a lot of games there's a lot of huge and cool environments or areas. They may feature lush interaction, cool challenges, points of interest, or just contain a shit-ton of stuff that you can theoretically do, but wouldn't be practical or optimal in the main game. Some games thus feature a bonus mode where the player can interact with all of that with either reduced constraints or none at all.
In Sandbox Mode, the player usually can't die or get a game over, due to having unlimited health/time or an absurd amount of it, or some other form of game-ending danger removed. If there are in-game resources, they'll likely also be infinite or maxed out to let the player experiment freely. The mode has to be unlocked almost every time, as obviously developers have to let the player try out the main game they paid for first, and in such cases may overlap with New Game+. The game may also give the player certain abilities that are not normally available, like flight or game parameter changes. In most cases, nothing done in this mode will count towards achievements or other challenges due to generally becoming extremely easy, unless they're specific to the mode.
Websites that are considered part of Web 2.0, including wikis, frequently have sandboxes (like our Wiki Sandbox) to let users test things like formatting as well. If the website also puts a time limit for content creation, it may remove it for the purposes of letting them try it without pressure of a timer. However, if a sandbox is publically visible, users are expected to still have some decency when they play around in it.
Not to be confused with Debug Room, which is more for the programmer's benefit than player experimentation, is typically found by typing in some secret code rather than given normally, and features options that affect the main game. This is also different from Endless Game in that whether the endless game ends actually depends on the player skill, so if the player sucks, they won't be able to continue, but here they don't have to worry about that and don't have the sense of progression either. Additionally, the Training Stage is different in that it's, well, to actually train (usually combos for fighting games) and often made simplistic on purpose (even if it does let you test things out, it's still often done within boundaries of regular gameplay). And obviously not to be confused with the Wide Open Sandbox genre.
- Ape Escape games had a few "extra" modes. Some were Time Trial mode, but another was "Free Play" mode, which gave you infinite lives within the level you chose the mode for. This mode made it so the player could explore the level without having to worry about dying and running out of lives. In the third one, there's only one major flaw which can ruin the experience: Getting caught with your own Monkey Net. Why? It sends you back to the Hub Level, which normally wouldn't reset much, but your progress in "Free Mode" is not saved.
- Bloons Tower Defense games starting from 4 (which was likely the Trope Namer) include a sandbox mode which is unlocked at rank 25/26 in which you have nearly unlimited money and lives and you can test all towers as well as bloons in it.
- Cities: Skylines comes with this in the form of two included mods, one which unlocks everything and another which grants unlimited funds.
- In Colobot, after you unlock a planet in the normal missions, you also unlock its sandbox version, where you can build any of the buildings and robots you have already unlocked in the main campaign.
- Dead Rising 2: Off the Record features this and is Exactly What It Says on the Tin. The player has the freedom to do everything they could normally, but with infinite time. The game goes through a loop of the games 3-4 day cycle, every survivor's a psychopath, and there's challenges to do to unlock Protoman's outfit or just get achievements, and if you got a buddy to play, co-operative version of this! It's supposed to be Dead Rising 1's Infinite Mode's spiritual successor. In DR2: OTR Dead Rising 1 had Infinite Mode which had Frank survive and vice versa. Could be averted since it got a hunger system exclusive to DR1 which depletes Frank's health one by one after 120 seconds, giving you finite time to roam around the games world freely. Another difference between the following Dead Rising games are that DR1 Frank will die at some point, since health items are finite and he can only go on for so much time before dying from starvation, whereas DR2 had a multiplayer mode instead to earn cash, while DR2: OTR followed it by the book.
- Diepio has a sandbox mode in which there's no threat from other players (unless they're invited through a party link) and you can use cheats that let you switch classes, level up instantly, or activate god mode.
- Drunk On Nectar: The game's sandbox mode lets you freely create the garden and ecosystem.
- Dungeon Keeper The second game adds a my pet dungeon mode where you are in charge of when enemies invade.
- Geometry Dash has practice mode, where the player can set checkpoints (while the base game has Checkpoint Starvation on) in the levels, from which you instantly respawn. This makes it very useful for practicing all the hard parts of a level, and is outright vital if you wish to take down a demon level of any kind.
- Insaniquarium has a sandbox mode which can be accessed after earning either the Silver Trophy or the Gold Trophy from Challenge Mode. Entering the Konami Code at the main menu screen will bring the player there. Within it, the player can spawn almost any kind of fish, pet, or alien using hotkeys and change backdrop with plus and minus keys.
- Jurassic World: Evolution: A sandbox mode can be unlocked on any island which has 4 stars earned. It lets you customise parameters like cash available and dinosaur escapes. The standard preset is meant to be like island management with unlimited money, while the creative preset removes most restrictions and management requirements. Each new dinosaur, building, or research item that has been unlocked through the campaign will subsequently be available for use in this mode.
- Katamari Damacy: One of the rewards you can unlock for certain achievements is an unlimited mode, where you can roll your katamari for as long as you want, without a time limit.
- In Kerbal Space Program the Sandbox mode allow the player to build rockets and other devices without any limits of funds and Tech Tree.
- Learn To Fly 3: A sandbox mode can be unlocked in which you can raise or lower many attributes such your speed, gravity, the amount of obstacles and control power. Just don't raise them too much or you will crash the game.
- Lemmings 2: The Tribes has Practice levels, which allow the player to choose any skills, and are large levels with a lot of room to play around. Their purpose is to allow the player to get used to what all the skills do, since Lemmings 2 has 51 skills, compared to the original game's eight.
- LittleBigPlanet franchise: Create Mode allows players to freely build and design using objects, materials, worlds, sounds, music, and tools that they've collected in the Story Mode. The player can only die if they will it, as well as start, stop, and travel back and forth though time to aid in building. The player can use this mode to create levels that other members of the community can later play for themselves.
- Minecraft has its "Creative Mode", where players have infinite resources to create anything they wish. In addition, the usual survival aspects of health and hunger are stripped away (preventing death), and you can now fly in order to traverse the map. You're unable to unlock achievements when playing in this mode, however.
- The Movies: There is a sandbox mode which allows you to choose your starting year, your starting budget (from $100,000 to $100 million) and has options you can choose to make the game easier. However, the years you can select and the items that are available to you in this mode have to be unlocked in the story mode, although manually modifying the unlocking.ini file can also do the job.
- Musaic Box lets you use Creations Mode after beating the game, in which you can use any of the in-game songs and shuffle pieces around a large board freely to make your own music for fun.
- Pixel Gun 3D has a Sandbox mode in which you cannot attack at all, making it a lounge for players to relax in.
- Planet Zoo has its Sandbox Mode allow players to start zoos with unlimited money and resources, all animals available, and all research completed to let them be creative with zoo design from the get-go.
- Railroad Tycoon II has "sandbox mode" as one of its options; in sandbox mode, the player has unlimited funds, can access every train ever made (regardless of the in-game year), and can also edit terrain.
- RollerCoaster Tycoon has Mega Park, a map unlocked for completing every base game scenario. Every type of object can be researched here, and you have no objective. You are still limited by your funds, however. RollerCoaster Tycoon 3 added a true sandbox mode to the series, giving you a wide open space to build and unlimited funds with all objects unlocked.
- Scribblenauts's title screen provides a free playground to summon arbitrary items and do whatever you want with them, without worrying about mission restrictions or Maxwell's health.
- SimCity (2013) includes a sandbox mode, which starts the player off with §1,000,000, cheats enabled, and all buildings unlocked.
- SimEarth: on the lowest difficulty level, there's an unlimited energy budget.
- While The Sims Medieval is normally more goal-oriented than its parent series The Sims, with various "Ambitions" you can play that have a limited amount of play time because you have a given amount of "Quest Points" to spend, completing the first ambition also unlocks "An Eternal Kingdom" which allows you to play around in a kingdom with no limits. Technically you still have to select a Quest to play, but "Free Time" is available as a Quest, allowing you to play freely in Medieval.
- Terraria has a version of this in Journey Mode. It grants the player a number of options, such as God Mode, changing the world difficulty on the fly, and disabling the spread of the world evils. It also features an item duplication system, but notably does not give the player the ability to duplicate all items from the start. You instead have to research a certain number of each item before you are able to duplicate it. This means even in Journey Mode a player still needs to progress through the game to acquire items, but you can gain an infinite supply after that. And since money is represented in coins which are treated as an item, they too can be duplicated.
- Tropico has a few sandbox mode variants; one is an infinite game with no goals or score, and in addition the player can also choose to set the political and economic difficulty sliders to sandbox mode (the description for the political sandbox setting is "at this level, not even political scientists can mess this up" and for the economic setting is "if only real life was this easy").
- Valthirian Arc 1 has the Breeze Arc mode, also called Sandbox Mode and Endless Mode, which removes the inspections, letting you play and build the academy without worrying that you won't meet the fame requirement and the game will end. However, you can't earn the "Perfect Year 1" in-game achievement, get achievements on websites that host the game or submit your score when you're playing it.
- In Warframe, Cephalon Simaris sells a Simulacrum Key for 50,000 standing. In the Simulacrum, you have endless health, ammo, and energy pickups, you can freely change your equipment, you can spawn in any enemies you've filled out the codex entries of, and you can enable or disable invulnerability and the enemy AI. Later on, the developers added an alternate layout for the Simulacrum that can be acquired by participating in events such as Operation: Scarlet Spear.
- Zoo Tycoon has Freeform games as an alternative to scenarios. Here you have no objectives to complete, and can design a zoo as you wish in one of many maps. You don't have unlimited funds, but can choose to start with anywhere from $10,000 to $500,000. You also still have to research various upgrades and unlock objects. The Marine Mania expansion pack adds a "Kids Map", which takes it further, starting you off with everything unlocked. Zoo Tycoon 2 retains something very similar to the first game's Freeform mode, now called Challenge mode. The mode actually called Freeform in 2 is even more of a sandbox, giving you unlimited funds and unlocking all animals and objects from the start.
- Drawception has an area that's appropriately called the Sandbox. In it, you can draw whatever you want without being prompted, and there's no time limit (though the timer is still there).