I was playing around with the physics of skulls, maybe something didn't come back the way it was. Need to check profiler.
I did mini performance fix. Let's see how it works.
only minimal effect; you introduced something w/the milestone stuff that is just doing way too much.
i'm just into level 1 and it's just ... no bueno .. see the lag:
sidebar: you need to introduce a debouncer on the skull 'hit' audio, i'm certain there's some performance bit there, but it's not the big game-breaker.
yes, you did, good job. can you take a moment and think about changing two things about the score display:
1) fixed width, period. the fact that the entire line of text moves move left and right on change is... not amazing UX. the only thing that should move is a changed number.
2) the color, with no outline, is difficult if not impossible to read when skulls are stuck at the top in a new level. consider moving it to the left above the hell shop.. and .. please #1.