The only Star Trek game on the PSP, Star Trek Tactical Assault featured two mission campaigns based around the original Star Trek films era. However, there were a number of elements left out of the main game, but which remain accessible.
The first is a debug mode, where the player can select any ship on a particular level to play. It also includes a camera function to look at ships from different angles. Debug information such as FPS could also be seen.
The E3 demo is hidden in the game’s content and can be accessed through CWCheat codes. It is very similar to the first mission in the game.
There are two other unused missions (one Federation, one Klingon), as well as a “combat test”. This seems to be a Skirmish mode mission with a set number of ships.
The game has a number of unused models, which seem to be from the original TV show rather than the films. The main one is a planet killer from The Doomsday Machine. It is not to scale, though.
There are two shuttle models (albeit without textures), one from the original show and one from the first film. The models can be flown like any other ship in the game, although the animation is jittery at times.
There is more information at Edward Kirk‘s website: