Tested on Linux (Debian)
+For keyboard controls only
+For green money waves, they break the monotony
++For not having to pickup shop when it drops, I would just let it sit until I collect more money
-For making shop gravitate to me after picking up item that makes stuff gravitate (Running away from it was not fun and felt like I was bound to lose that race before I collect enough money for items
+For music (but I think it can desynchronize badly if I spend too much time in pause screen on picking item
+Pogo with enemy between wall and character is nice
-Items really badly need graphics (even from msPaint, pic attached happend to me and I did not know what I'm upgrading) 
-I'm autistic about numbers but knowing how much +damage is (+1/s or 10/s) or discount is -15% or -50% would be helpful for me
-Drops slowly fade away. If I missed it initially I def will miss it when there is 70% transparency. Make drops catch my attention blinking after some time (like 30s) and than increase blinking frequency until they despawn.
-Char 1 and 2 are really similar
/Spin for boons. I assumed it doesn't do anything yet, allowing me to stop it is nice but if it stopped by itself after some time that would be nice too. Gamba to get the big ones did trigger right emotions in me.
/For first half of my playtime I assumed number on top of a clock is time remaining till next wave, than I realized it doesn't go down with time. I can't tell if it should stay the way it is or not.
/Would suggest adding some variance in speed of enemies
/Sometimes evolutions for items were clear on what changed while others not so much
I played 3 times (1 time each char) and won only on the first one.
There is no punishment for damage to your base early because it will re-heal. Not saying that's good or bad, my expectation coming in was that I will get punished over time for my mistakes, where it's rather about wave of enemies bursting you. Both have upsides and downsides.
Smite - Problematic kind of item. If I have to use it it means I'm in bad situation but long term it will only get worse because I missed out on some DPS by buying one time burst. On the other hand you can make 1 or 2 waves that have Smite mandatory to use to survive just because it's so overpowered (Assuming it would drop on those waves). I get that when you run out of items in pool you have to put something there but I'm not convinced.
I tired starter items and 9 more - balance was off but I had hard time telling if item is early game or late game due to no knowing DPS and such.