Finished Gun = Finished Game

It's the Binding of Isaac for hardasses. BoI has a more intriguing presentation and "lore", but this is just so much more mechanically refined.
Some enemies can suck a fat one, and a few secrets I would have not found out without a guide, but as far as arcade-y time wasters go, this is close to the peak.

Also they did a great job not making the puns and references to other media insufferable, at least to me (looking at you Ready Player One), I prefer it to the gross-out designs in BoI.