Really, really good! I've always loved tower defense games that allow you to play with enemy pathfinding, but can never find any, so was absolutely delighted to play this.
Nice variety of towers and enemy types, and the health sacrifice mechanic worked very nicely with tangible rewards but a big tradeoff.
Would love it if endless mode escalated the difficulty a little slower so I could really explore filling the map with towers and maximising enemies travel time.
I did try to completely block in the base - nice catch making sure I can't cheat!