Apocalypse is an action game / third person shooter released for the PlayStation in 1998. The game was initially developed by Activision Santa Monica, but the team had some problems in fulfilling their original concept, that was seen as “too ambitious” for the PSX hardware. Apocalypse was doomed, but as Activision paid Bruce Willis a lot to have his likeness and voice in the game, they decided to dismiss their Santa Monica Studio and hire Neversoft Entertainment to finish the project.
Neversoft was able to complete the Apocalypse project, but the original concept was changed into a more linear shooter. As we can read at the Playstation Museum, initially Bruce Willis was meant to be a sidekick to the main character, but when focus testing revealed that people wanted to play as Bruce, he became the main protagonist.
In the gallery below you can see some of the beta builds with different characters and levels. Some images (a 10% complete build?) were found by Celine in GamePro #90 while other screens and footage were preserved by the Playstation Museum.
There’s a beta version of the Neversoft game released over at Assemblergames (http://assemblergames.com/l/threads/apocalypse-ps1-prototype.64931/). It has a menu with four of the game’s levels, but the others can be accessed by codes. There are some differences to the final game in terms of enemies and level layout.