Really fun! Captures that classic arcade game feel perfectly.
I'd love some temporary power-ups, special abilities gained from collecting specific pills or killing certain monsters, etc.
Could also collect a set of certain things to kick off a super short bonus round where the screen fills up with pills so you're rushing to collect as much as you can before time runs out. Stuff like that would give the player some strategies to explore to find ways to achieve higher scores.
On that note, how about a persistent old school leaderboard where players can enter their initials, etc?
Anyway, just some ideas to plus up an already great game. Thanks for posting it!