One of my favorites, honestly. The pacing and aesthetics are great. Sometimes you just want no-frills direct to fun games.
Alas there's a bug where it shuts down ... around the 3rd round I think? It's always in the upgrade area, like if I try to double upgrade. Past the second upgrade. The music keeps playing but the screen goes dark. What's weird, though, is I don't recall the bug being there before. I have updated Firefox but other than that I can't think of anything to narrow it down.