The game was pretty fun! Once I got past the initial stage of upgrading the weapons, I was able to take down the crowd of mice, rabbits, and pigs! I maxed out all the upgrades, but I didn't see any medals to unlock under the achievement tab.
After several rounds (I think around 34?), the growing crowd moving towards me were freezing and jittering everywhere. This made it easier to dodge them, despite the lag. I was able to stay in one spot where the mice couldn't reach me, even though they had the free space to do so.
The best upgrades were range and reload speed. The reload speed upgrades made the clip size upgrades moot! It was fun seeing them bounce really far away with the force upgrade.