[Multi] What the Hardest Game You've Played?

[microgamer2vs2]

I tried I Wanna Be The Guy for a little bit, never tried too seriously though. There was this one somewhat similar game which was basically Mario but with a Cat and the game was out to kill you because it basically threw out all conventions you knew about side-scrolling platforms out the window. I forgot the name of it though.

As for other difficult games, there's the whole Touhou project series. I'm starting to get decent at Normal, but I hang out with a few Lunatic players in the chat room I frequent so their skills stomp mine.