Thanks for the feedback, the snake is a tough one, as its movement will have a slight delay due to being grid-based, but I'll see what I can do to improve that experience. I'm also considering undo/redo actions when in that mode.
Better minion management is definitely coming! It's very important to get right, as you've discovered, so I want to make it as painless as possible.
Yes, great strategy with delaying the keys! It's extra reward, but of course some risk as well. Coins (and power-ups) are added in each wave, but you get fewer each time until eventually it will stop spawning new ones.
The shaman can be really powerful if you stack a couple goblins in front, but we're going to be revisiting balance across the board. Some are pretty worthless right now while others are seriously OP (I'm looking at you, Vamp and Jack).
Thanks so much for playing and for the great feedback!