Almost finished...

Added Part 3- Find the helicopter after the bomb is set.
Added dust video effect when helicopter takes-off/lands.
Added end sequences for win/lose.
Added 2d fire animation if bomb detonates.
Updated the inside of the temple with some "alien vs predator" art panels.
Added some more music and sound effects ("Go!..... Get to the chopper!").

So, it's nearly finished - the player can now drive the tank, shoot the Predators, be caught/killed by the predators, collect the Marines, Open the temple door, hatch an Alien Egg, Impregnate a Predator with the Face-hugger, Find the helicopter as it lands during the bomb countdown, escape in the helicopter...or be killed in the nuclear-blast.

I just need to add parabolic bullets and a simple RADAR, clean up some of the timings for the end of the game, then I can add more detail to the forest (with more vines and better tree and plant models) and add some better textures/decorations around the scene - possibly a few more voices from the movies.

I added some cheats to test the game: Tap "1" to spawn at the temple with all 5 marines - Press "2" to toggle enemies on/off.
*Note: Enemies need to be (on/enabled) to be able to hatch the egg  and impregnate the predator with the face-hugger!