Did you get all the way through the insanely difficult I Wanna Be the Guy? No, you didn't. But you can play the sequel anyway.
Developer Kayin has released the freeware game, I Wanna Be the Guy: Gaiden, the first part of an episodic "side story" that adds a bionic arm function, giving you a new dimension of moves you can time poorly and die from – or, more optimistically, methods for getting out of the way of some random, giant Street Fighter sprite.
More content is expected for the Windows-only Gaiden, and of course more episodes. "How many episodes will there be," Kayin asks rhetorically. "Who cares, I'm playing it by ear."