The power-up system at the beginning is really well done! I like the selection of all the different slimes, and their names and faces are really cute. There is a drop-off in excitement after you manage to kill the first enemy, after that the game becomes easy yet drawn-out.
I bounced around the town for a few minutes after I got it down to "1 enemy left," and I wasn't sure if it was still out there somewhere or if the game was counting me as the last enemy. But I bounced around for a long time and couldn't find him so I quit. Don't know if there was a win screen somewhere that I missed.
Sound effects are well-done, too!