Played it. Very fun! Addictive. I liked that there's a tree with upgrades. Shooting felt great. The first screen was cut off at the top in 3440x1440, but it's not particularly important. I died because of getting hit from behind and I didn't really have any way of noticing it (imo), but I assume that's by design to make the player look around more. Flying ragdolls were a bit weird, but funny I guess, I would expect that from the shotgun, but it was even more weird when it happened after a nailgun shot. Nailgun didn't feel like it was worth unlocking at all, maybe later it will be stronger, but it didn't feel fun to use for me, mostly because of the lack of damage, maybe it would be more fun if you could shoot if without zooming in? The zoom in has a small issue btw: when you aim at the zombie and then you press the right mouse button to zoom in you no longer aim at the zombie, which is slightly annoying, but you can get used to it. Coin upgrade didn't seem to be worth it compared to other upgrades. Other than that the gameplay was a ton of fun and I played it a lot longer than I expected. Good job! And good luck with the release!
Here's my gameplay (with some voice over) if you want to check it out: