LEGO Dimensions is a multi-franchise toys-to-life game featuring characters and levels from 14 licensed franchises with additional franchises due to arrive in the future. The game contains elements from the Middle Earth franchise, The LEGO Movie, DC Comics, The Wizard of Oz, The Simpsons, Back to the Future, Scooby-Doo, Doctor Who, Portal 2, the Midway Arcade franchise, LEGO Legends of Chima, LEGO Ninjago, Ghostbusters, and Jurassic World.

Functionally the toys-to-life aspect of the game is similar to competitors in that the game comes bundled with a USB portal onto which figures are placed causing them to appear in game and available to be played. The game starter pack and additional expansion packs come with LEGO minifigures that the player is instructed to build before play, with each minifigure coming with a special vehicle or item that can be built using instructions presented on screen in game. Additionally any minifigure can be used anywhere within game regardless of franchise-affiliation.

The starter pack for the game comes with a number of levels forming an overarching plot concerning the 'Foundational Elements' which function as cornerstones to time and space, these elements are across multiple universes representing the various franchises available for purchase with the game. In addition to these main story levels, every franchise gives the player access to an 'Adventure World', similar to the hubs of other LEGO games giving the player miniature open-worlds with a variety of puzzles, races, and quests to complete in exchange for collectable Gold Bricks. Expansion levels are also available for the game in packs marked as 'Level Packs' which in addition to giving characters also give a downloadable level.