Aliens: Thanatos Encounter is a 2001 top-down shooter video game developed by Crawfish Interactive and published by THQ for the Game Boy Color.
A group of Marines is on their way back from a training mission when they get awakened from hypersleep by a distress signal from the Weyland-Yutani space freighter Thanatos. They go to investigate and find that things are wrong, way wrong...
Players choose one of five marines, each with his/hers own special attributes (speed, stamina), and then get briefed for your mission. Players get an overhead view of his marine, bottom of the screen is either one weapon and a motion tracker or just a gun that must be held with two hands OR two guns John Woo style. Gameplay consists of making his way through about 12 levels with mission objectives ranging from save the lone scientist to finding a new experimental weapon to kill the Queen.
Little tidbits from Rammstein2452
The following is taken from GameFAQS:
It is password save which is kind of a pain but oh well. For all you Aliens fans there are ALL of the guns. There are many boss fights or swarm fights where you get prepped with guns-ammo and get thrown into a 5-10 minute battle with a huge boss Alien or swarms of Aliens in one room. There IS a power loader, actually about 10 scattered along the game. You take control of it automatically and it is pretty much a HUGE boost in armor, taking hits for you, still allowing you to use both hands for guns. When you die you send in another marine to play the level, and if you want you can find your fallen comrade in one of the holes (you have to play the game to know what I mean) which is guarded by Aliens, and save him, otherwise he dies. The game is normally a heated shooter, but when you're life is down and ammo is sparse it turns into a suspenseful strategy game, shooting accurately and running from hoards. Trust me on this, you'll like the game, a lot!