After my rant concerning the poor quality of space ships against alien attacks I stumbled across Alien Swarm. Free on Steam, Alien Swarm takes you and three other marines into abandon colonies overrun with insect-like xenos. In addition to something you can spend your time on, it subtly conveys the importance of survival strategies in horror situations. My favorite example is that friendly fire is almost always more dangerous than enemy attacks, don't get in your ally's way. Good luck, and don't shoot your friends, unless they are zombies trying to eat your brains.