I'll never forgive Disney (among many other things) for cancelling the Star Wars 1313, this demo made me extremely hyped back in the day. It had so much potential! What is that one game (or games) you rooted for but was never released?
Also, I know I would've played way less Pokémon if development for Halo DS had been finished. Such a missed oportunity as well; we'd probably have Master Chief in Smash now if this had happened.