Recently i am really into this 2 games.
Guns, Gore& Cannoli is a 2D horizontal action shoot 'em up. A sort of a forbidden love child between resident evil and metal slug. Even at normal difficulty is hard enough to keep you focused but easy enough to let you relax and enjoy headshots, witty one liners and cannoli. To my surprise, there is a plot.
Is not really deep but is not shallow either. Avoid the sequel(GG&C2), is bad as bad can be 
20XX is a lot of megaman X and (alas) a little roguelike. You have a totally non suspicious blue armored buster armed reploi… i mean robot, who is a blonde female, and a red armored one with a light saber. Sadly here there is actually almost no plot (even for MMX standards). If anyone is interested i rec buying also the 3rd char, hawk.