If you're not going for the no-death trophy, just go ahead and die once when you enter a level--you'll be able to see how many coins and monsters are on that level.
Harder defense quests depend almost entirely on your luck at killing the first few enemies. If you miss, they make it to the other side and since you cannot place any units yet to block them, you're screwed. I think making enemies worth more gold apiece or your own units cost less gold to place would easily fix this.
This game was much improved from the first 2. I liked hearing some music at last and I loved that the mini-map now marks where things are. However, I think you still need to 1) make ppl have to earn the cheats if you want ppl to actually play the game and 2) make the screen larger and put the mini-map somewhere besides the playing field. Even though it goes transparent when you walk under it, its still very annoying.
Evolution is a natural part of the life cycle. If a frog evolves the natural ability, for example, to stick his tongue to any wooden surface, the flies will evolve abilities to counteract that, such as knowing how to drive a bulldozer. Its all part of the Circle of Life.
This game needs a feature where you can bring your party over from one chapter to the next. This would require a lot of work, but I think it would increase its appeal greatly. Besides, this is going to be multiple chapters long anyways right?
I think the 50x multiplier(hard badge) is much easier to get than 1,000,000 pts(medium badge). Just focus on staying high and grabbing gems when you can. Don't try and make crazy jumps just to get that one extra gem; it'll slowly build.
It seems to me that there should be some penalty for dying for the game to be more balanced. As it currently is, I'll fight a monster even if I don't think I'm strong enough because the worst thing that could happen is that I get a free ride back to town.