Every time I submit a run I think it will be the last but then I find another little time save here and there. Ending could be much cleaner/faster. I don't think there's many time saves to find apart from the final level, mostly collecting the 5 orbs on top of the tower then getting down. the rest is pretty set in stone (although the firebars can be gone through backwards if you time it right I'm just not sure if it's faster and it's much harder to land on the middle platform blind.)