That was very fun! The mechanics are clever and engaging, and the character designs and style are charming and readable.
I think the most overpowered thing about Pacifier is that converted enemy bullets also convert all enemy bullets. Otherwise, I think (personally) it could be a default mechanic.
The audio balance seems a bit off; the music by itself is a bit quiet (hovering around -34 LUFS) while the sound effects on top of it are a smidgen loud (hovering the audio between -20 and -13 LUFS and sometimes peaking above +0.0 dB).
Also, while it's great (and much appreciated) that the sound effects don't stack endlessly, some of the sounds are prone to being clipped awkwardly. Maybe a couple of the pool-ball hit sounds can stack if they're not playing at the exact same time? I'm not sure of the best solution to that.
All-in-all, fantastic! Great work!