Had a lot of fun playing this. Good overall system design, whereby you really had to play and test things out to work out which cards were good. After i felt i had seen all the cards and the game difficulty was not pushing me to innovate i put the game down (i was on on level twelve).
Some balance suggestions *(2-5-18 update) you can take or leave:
-toolkit is problematic since it is a draw card which pays for itself (draw two lose two) essentially allowing you to play as if you had a much smaller deck
-all attack cards fall off in power level very soon- because so many monsters spawn in the later game it is very poor tempo to try and defeat them (the only seemingly viable attack is the one which turns them into grass, cool card design)