Gun Bros is a simple top-down shooter in which you fend off waves of robot/alien creatures on various different planets. What’s most impressive about this game is the sheer amount of content you can unlock. As you earn money by gunning down wave upon wave of baddies, you can spend it on guns, outfits and power-ups to make you a more effective killing machine. You can even make your character available for others to use online, allowing you to gain XP even when you’re not playing. It’s hard to tell why Gun Bros is free and what the developers gain from constantly releasing new weapons and levels for it, but I’m sure no one’s complaining.