On the Mac version it runs waaaaaay fast, animation-wise, because LÖVE 11 for whatever reason doesn't actually do vsync. The (dt) parameter sent to love.update is important. Here's a quick-and-dirty fix.
No vsync on Mac? :o
Thanks I'll add that fix. I shouldn't have been relying on 60 frame vsync anyways, as I discovered when I ran the game on a 144hz display.