Absolutely love it, the graphics are clean and very nice to look at, and the ambience is great :D (especially love the shotgun sfx lol, so much oomph)
It has great replayability, and the enhancements are funny while still being a goal to work towards of sorts :P
I do really enjoy the amount of strategy in this, both in picking upgrades for immediate use, and effectively investing in upgrade branches for later. The enemy buffing is also super interesting (the skull rating is so helpful) Also I like that the player is heavily encouraged to go and scavenge, it really adds to the tenseness of the gameplay!
My only constructive criticism is that sometimes the upgrade orb things can spawn quite far from the tower, and often I don't even realise they're there as a result, even with all my 'running' around D:
sidenote: can an eyeball even run???
Oh and the 'be not afraid' bit is honestly really cool, I really love the design of the 'unnameable beast' hehe, and the fact that you can't kill it, just evade, adds a fun and unusual challenge (usually resulting in me getting my butt kicked but hey what can you do :P)
In short: awesome game :D And thiiiiiis is a very long comment, oops :v