Most video game demos simply use aspects of the game. Sometimes these demos use the first level of the game and sometimes they'll use random levels. In contrast, self-contained demos are not levels from the game itself. They use non-canon stories or side-stories to give you a feel of the game without spoilering anything or reusing a level.
Compare to Tech Demo Game.
- Half Life:
- Halo 2's demo at E3 2003 was an original level set in what became the New Mombasa levels. While the core mechanics demonstrated in it (dual wielding, vehicle hijacking, and enemy Brutes) were kept in the final game, the demo levels ran on an entirely different engine that was said to crash if the player went just the slightest Off the Rails.
- The early access levels of Ion Fury are a series of short, but still expansive, levels, which is different to the levels of the final release, although it's available as a bonus content in the final release.
- The Jedi Knight II: Jedi Outcast demo was about investigating an enemy base that had no connection to the game itself.
- Metroid Prime: Hunters had the demo Metroid Prime Hunters: First Hunt that was included in Nintendo DS packages. It has several differences with the final game notably the fact that there actually were Metroids in the demo and had a secret cutscene.
- Jurassic Park: Trespasser was an unintentional example, since the demo map was a level that was Dummied Out of the final release version after the physics engine bugs that made the demo nigh-unwinnable couldn't be resolved in time for the release date.
- Beating Carrion unlocks the level from the Alpha demo.
- Silent Hills had one of the most prolific single cases of this in the form of PT, which was quietly released on the Playstation Store masquerading as an indie game before the Twist Ending revealed that it was a Playable Teaser for a new installment in the Silent Hill franchise. However, Silent Hills was later cancelled, meaning that PT now exists as its own island (and an increasingly fleeting one at that as it's since been removed from distribution). Given how the demo is mechanically unlike any other previous game (first-person exploration horror instead of third-person Survival Horror gameplay) and has such a cerebral yet localized plot, it's not even known exactly how representative of the final game it would have been.
- "KITCHEN", "Beginning Hour", and "Lantern", for Resident Evil 7: Biohazard. None are referenced in the finished game, and "KITCHEN" is the only one that clearly ties into the canon story (accounting for one character's death which we know happened but otherwise don't see take place).
- In the demo for Lemmings 2: The Tribes, four exclusive levels are featured, one of which is similar to one of the same name in the full version, but with slight differences.
- In order to avoid spoiling the game itself, the creators of The Stanley Parable created a self-contained demo to promote it. The entirely original level contains the Narrator leading you through a tour of what is supposed to lead up to the Stanley Parable demo, but ends up becoming a surrealist nightmare. They even sent special editions of this demo to Let's Players Steam Train and Revision3 containing bits of dialogue directly addressed to them.
- Glider PRO: "Demo House" served as the playable demo as well as the game's tutorial and Attract Mode. Though included with the full game, it is entirely separate from the game's primary scenario, "Slumberland."
- Space Quest 6 had a demo with an entirely different story about the ship Roger had been transfered to being attacked by knockoffs of the Borg.
- Shenmue had a Japanese exclusive demo called What's Shenmue?, released as a preorder bonus to make up for the game's release date being postponed (the demo was released the date the game was originally going to be released) and also made available as a freebie with Famitsu. The demo features Ryo searching for Mr. Yukawa and saving him from an assaulter. It's then revealed that the entire demo was a dream made by Mr. Yukawa, which goes back to work on a marketing campaign for the Dreamcast.note
- The Awesome Adventures of Captain Spirit serves as a free prologue to Life Is Strange 2, centered around Chris Eriksen, an imaginative 9-year old boy who lives alone with his father and dreams of being a superhero named Captain Spirit. The extent to which this demo impacts the story of Life Is Strange 2 is unknown, though it has been confirmed that choices made in it as well as in the original game will affect the sequel in some way.
- An now-removed free iOS-only version of Angry Birds contained levels that weren't in the full version. That was until 2015, when the ability to unlock (nearly all of) the first four chapters via watching ads was introduced, leaving those 24 levels as an artifact of an past time.
- Bravely Second did this with its demo. You controlled Yew, Janne, and Nikolai on a mission as the Three Cavaliers, set before the game's beginning.
- Pokémon Omega Ruby and Alpha Sapphire had a downloadable demo where you played as the male lead (named "Orlando" in the demo) set in Mossdeep City where you encounter Team Aqua and Team Magma. It also features the possibility to catch a Glalie (a Steelix in the Japanese version) with his Mega Stone and transfer it into the final game, where both the Pokémon and his stone are normally available only towards the end of the game's main story (or not available at all, in Steelix's case)
- Pokémon Sun and Moon had a downloadable demo where you played as the male lead (named "Sun" in the demo). It features him arriving in Alola with his mom, but it's depicted in a completely different from the actual game. In the demo Sun receives a Greninja with an exclusive ability called Battle Bond, allowing him to turn into Ash Forme after defeating an enemy Pokémonnote , and then has to complete an Island Trial exclusive to the demo, set in Ten Carat Hill and featuring a Totem Hakamo'o. Completing the demo also allows to transfer the Greninja in the final game, alongside a bunch of items you get doing multiple subquests after completing the demo's main plot.
- The original StarCraft I demo was a campaign made of four levels that play before the events of the actual game. It was later made available as an extended version with additional missions that could be launched as a custom campaign from within the game.
- Uniquely in the demo campaign is that it has branching path that lead to different mission and opposition depending on your action in a mission.
- Empire Earth has tutorials that are unconnected to the game's campaigns, like Phoenician settlers or Roman soldiers.
- The demo of WarCraft 2 featured two campaigns of three levels each which were not featured in the game proper.
- The demo of WarCraft 3 was an extended version of the tutorial prologue of the actual game, featuring three extra levels. These levels were included as a bonus campaign in the Expansion pack.
- Homeworld: A cut-down promotional version of the first game, variously known as the "Raider Retreat" or "OEM" edition, contained the first four missions from the regular game and a fifth completely new one, which would later turn out to be cut content that was removed from the release version for being unreasonably hard for that point in the game and not doing much to advance the plot.