The armies consist of 9 creatures; each one is a combination of any two animals from a list of 76 (51 with no downloads). Many animals possess inherent abilities to add more strategic depth to the game. There is an extensive single-player campaign as well as online multiplayer functionality with different game modes, add-ons, custom maps, mods, and scenarios.
On November 12th 2015 Impossible Creatures was released on Steam as Impossible Creatures: Steam Edition, by Nordic Games. The Steam version includes all patches and expansion packs released in the past, the IC Online servers reimplemented through Steam's cloud service and the game's modding SDK included in the package alongside the Mission Editor originally available within the game's files; potential Steam Workshop support is in the works. The Steam Edition is also optimized for modern computer systems and software.