It is the year 2036, and NASA has outdone themselves. With the aid of the European and Japanese space agencies, they have Saved the Hubble Space telescope, finished the International Space Station, colonized the moon, saved the planet from a huge asteroid, and sent a manned mission to mars. Unfortunately, the 6 crew members of the Mars mission mysteriously disappeared from the surface of the planet, transmitting only a weak distress signal. As an reconnaissance expert and hardened space marine, you have been sent to recover the Mars base and find out what happened to the astronauts. Once there, you visit their last known location, and find signs of a struggle. While scouting around, you are attacked by a small UAV, and you play dead, thinking that you have been terminated, the robot returns to base, with you perusing just out of the range of its sensors. The UAV leads you to an underground military base, nearby which you find bodies of the crew. They had been taken hostage by a hostile alien race, and when their usefulness wore out, they were executed. As you fight your way out of the base, you discover an unraveling conspiracy, the aliens have been making deals with communist rulers and dictators since World War I, bribing them to destroy the planet Earth in exchange for the secrets to teleportation and faster-than-light travel. You also discover a planned attack on the United States, to be executed by China and Korea, with the Aliens dealing the final blow. You make it back to your ship and begin your flight back to earth, bearing information that is key to the survival of the universe. When you finally get back, you find that the war has already started, and you land on the moon instead. There, you tell the scientists about the Aliens, and they come up with a radical plan to destroy the Alien base before their super weapon is ready. Fighting hordes of enemy soldiers and civilians mutated by radiation, you then scour the Earth, Mars, and the moon for parts to build the world's largest Hydrogen Fusion Bomb, and return to Mars to set a beacon that will guide the H-Bomb to the Martian Base, and escape the planet just before the bomb detonates.
As Jay pointed out, the game will need:
-Cutscene at the beginning
-Mars Station and a fairly big outdoor terrain
-Mars alien base
-Cutscene
-Moon base
-Levels (at elast 4) in which you gather the ressources for the H-Bomb
-Mars base revisited
-Ending Cutscene
Which reminds me of Jay's other point:
8+ levels and 3+ cutscenes. In how much time do you want to achieve that?
In truth, the game does not require too many levels to be possible, but it does require very high quality levels, and several of them, so this could take a while, not to mention cutscenes...
