Unfortunately I don't have a Mac machine to verify it. The Windows build seems to be working fine. Does it happen each and every time, or are there some particular circumstances?
Good to hear that! Maybe the slo-mo tween is messing with the game logic somehow. Lately I've been playing with it turned off, as I found it not as appealing as I hoped it to be. I'll at least make sure it's off by default in the next update.
If you have time and will, I'd like you to check if the CRT shader causes jerky movement with the dynamic camera mode (press C to switch between the overhead default one, and the dynamic one, following right behind the player). It may as well be an issue with my old hardware.
I'm glad you like it! Stay tuned for future updates if I get enough feedback on what to fix and/or come up with ideas for new features. BTW, there are boss enemies every 20 levels, be sure to check them out! They may not be the most sophisticated and difficult ones, but I think it's a nice break from the usual baddies :)