At last year's PAX East, Super Time Force impressed many with its humor, art direction, and nifty time travel gameplay hook. Should you die, you can travel back in time to the point right before you died to team up with your prior self, potentially working to save your prior life in the process.
According to Capy's Nathan Vella, it was a great concept in theory, but in practice it made for serious balance issues, with difficulty spiking and flattening out in ways under-conducive to player fun. It was hard news to break to the team, but they took it in stride, and worked to re-think the time travel elements to make them both more variable and less over-powered. They implemented a flexible timeline system. Now there a lot more ways to choreograph exactly when, where, and what characters pop up in a level, and less obvious ways to exploit the time travel trickery to reduce legitimate challenge.
They also added a fat jedi and a radical sunglasses lizard man, so that's pretty good too. If I die before Super Time Force comes out, I really hope future me comes back in time to save me so I can play through the game at least once. Then I can die I guess.