This game is very good, but a few silly things keep it from reaching it's full potential. Enemies are too few and weak, machine gun is all you need, and there's no ammo issue, never need to pick up a single ammo box or ammo upgrade. basically the game's too easy, oh wait, it's NOT, because to get the medals you have to beat the turn clock. Now the game basically become an obstacle course instead of defeating an alien invasion. The medal requiremenst make hp and heal upgrades pointless. Flamer and bombs are basically puddle cleaners, shotgun, the highest damage weapon in the game, is useless since it doesn't clean puddles.
I wish the game become more about using your squad strategically to kill an overwhelming amount of aliens, where you need to find more ammo, and hp and heals are necessary to survive.