Ah, SUPERHOT. Used to play the cracked version a lot last year. I should get it for good sometime.
During a while I played a zombie survival game called The Last Stand: Dead Zone, but I left it like two years ago. It required you to login everyday to check the status of your base, survivors and stuff. It was fun at the beginning, but you had to grind your way to the top levels to access more stuff, and I eventually got bored of that.