Summary: I got this "Shooter" quadrilogy on special for 5bux a while ago and this game is the best of them. There's loads of character customization with room for multiple playthroughs depending on how you build your BALD. Chock full of old-school gameplay, bad dialogue, the worse voice acting since sega CD, the fun of this game comes from chewing through waves of cannon fodder with bigger and more ridiculous weaponry. Generic and forgettable.
Summary: There's Aliens. You shoot them. The title is very apt. However, you shoot a LOT of aliens in a LOT of different ways, it is always accessible yet challenging, and the graphics are simple, yet it works for what it is. Sigma team has a formula which it uses, and has thoroughly mastered: Make shooting 1 alien feel very satisfying, then add as many enemies falling into the body count as your brain can process.