Hello.
TL;DR - good shit
After sinking around 15 hours into gnocking out gnomes and making my way into the top 100 on the leaderboard, I've made a few observations. I'll start with the things I like first.
The movement and combat feel quick and responsive. Airstrafing 30 feet in the air while healing almost feels like cheating. The map feels large and small at the same time, which I'd say is a good thing. It's large enough to not be easily goofable, while also being small enough to see everything running towards you. Discovering the little secrets hidden around was definitely interesting. I'm not sure if the secrets are functional at this point, but being able to explore the map before you start allows you to speculate and theory-craft, which is always nice.
The mushroom jump pads can be a little finicky in terms of consistent output. Sometimes they work as intended, sometimes they do weird stuff, like turn all of your momentum into forward momentum and launch you across the map (there is no fall damage yet thankfully). I've noticed something similar with the skull mushrooms, where if you hit them or land on them at the perfect angle, they will fling you pretty far. It's honestly not terrible though, and it never ruined anything for me.
One of the few gripes I have is with the terrain. Your ability to traverse the sloped terrain is strange in its function, as some slopes act differently than others. This was never too crazy for me, but sometimes you'll get stuck for 2-3 seconds on a slope, and get boxed in by tiny gnome people. A frog got stuck on top of a tree and almost ended my run one time, which was funny but a little scary. Generally pretty good though.
The enemy AI is generally pretty good, though rarely, the smaller gnomes can get stuck on boxy geometry. The spot I saw this occur the most frequently was the hole underneath the boiling cauldron. There were some other spots, but I think none ever got stuck long enough to really be noteworthy.
During endless, the game starts to buffer a bit. After round 50, the latency caused by the sheer number of entities on the screen gets to be a little overwhelming. Definitely not an issue most people will ever encounter, but can become a little frustrating for those trudging through endless. It seems like the size of the horde also affects how fast things are registered, or if they are registered at all. Hit detection definitely becomes iffy when there are 300 gnomes standing around you. There have been plenty of times in endless where it seemed like a punch should have landed, but just didn't.
I can't think of much that would make the game better aside from the obvious, such as furthering upgrade progression, new upgrades, more upgrade rarities, more combat options, different playstyles, challenge runs, more movement options (crouching, sliding), etc.
Overall, a fun and addictive vertical slice! I can see this becoming massively popular. Mr. Moist himself has already played, so I'd say you're doing well enough.
Also, I agree with the last person, you should make a server of some kind for the game.