I enjoy the concept of this game a lot. I liked the decision making of having to choose between units and buildings. I found the dialogue interaction when failing especially fun. I also really enjoyed being on the side of the enemies!
However, I felt discouraged to continue playing the game because it felt like I needed to put in a lot of time into grinding through early runs where I was unable to do anything meaningful. This was due to needing to constantly spend my currency on temporary units rather than the buildings to survive. I'm sure it gets more fun when you unlock more of the upgrades but progress to do so was not as fun as I would have liked. I think letting units survive between waves would have allowed me to use the buildings more. I also felt like I was doing something wrong because I wasn't able to do anything during the prep phase when I joined the monsters due to lack of currency spent trying to survive.
I do think this game is very promising and could be very enjoyable with a bit more tweaking and balancing. Oh and I thought it was a great interpretation of the theme too!