I believe this was a flash game, but I could be wrong about that.
Your character is running around in video game landscapes borrowed from classic arcade games. One part, for example, has him dodging falling tetris blocks. And the game is very difficult, comically so. And that’s all I remember.
I think you might be looking for ROM CHECK FAIL, which can be found at http://www.farbs.org/games.html
I Wanna Be The Guy is the first thought that I had, like Ferret Herder said.
You can see an expert playing (and beating) this savagely difficult game here.
It has a lot of background from classic arcade and Nintendo games.