Every now and then I find a game that I'm determined to beat. It seems difficult - perhaps a bit ridiculously - but beatable.
I played the original version (1 gold per chest, etc) and got up to "The Carousel" mostly using max rats, max spiders, skeletons + ghosts, and then ghosts + dragons. When possible, I used the nest upgrades in a room, cleared it out, and put a better unit (ghosts or dragons) in it to get the benefits. When I switched to focusing on ghosts, I did the same with tombs.
I was kind of bummed to see the update, since I had almost won the game that almost everyone was saying was impossible to beat. (By won, I mean 3 stars on all levels and all hard modes beaten).
After the update, I started seeing the paladin/wizard glitch more often. (Creatures get attacked but don't respond). The only way to win is to build dragons in almost every spot. Upgrading them beyond lv 2/3 is worthless because they die from bugs/glitches. I also noticed that if you fast forward, sometimes a mass of units gets stuck in a room until you clear a nest. I even had one enemy unit walk off the screen - forcing me to restart the level.
Bugs:
+ Lair masteries don't work. They didn't work before the patch, and they still don't. The code is somehow overlaid with the tomb masteries.
+ Wizard/Paladin attacks while monster freezes. - May be a location bug, as it seems to occur more often when multiple enemy units move on top of each other, or when creatures are forced into corners/wall spaces.
+ Creatures freeze in place with motion graphic. - Only happened once or twice.
+ Fast forward causes creature pile-ups. - I saw as many as 9 in one room attacking one unit.
+ Wizard fire spreading. - Sometimes units two to three rooms away were hit by the wizard's attack.
+ Ghost creation/upgrade achievements display in-level as skeleton achievements.
Improvement notes:
+ Skeletons in v 1.2 are a better value than ghosts. They have the same attack power and health, with a more effective ability (critical strike).
+ Monetary funds are only barely enough to beat later levels if you have the right strategy. Due to the monetary differences, the game is clearly biased toward making the first levels ridiculously easy and the later levels extremely difficult. I often ended up with over 2k/1k in early/middle levels because of cheap unit costs.
+ More stars should be awarded for beating different difficulties. e.g. beat easy get 2 stars total. beat medium get three stars total. beat hard get 4 stars total. Good players could beat hard and get the maximum amount of stars right away, while new players could work their way up.
+ Masteries should all cost the same. 15 stars per mastery is too costly even in the later levels, and paying 75 per use in a room is extremely expensive. 40 gold per use for any room (nest, tomb, or lair) would be more balanced - considering that weaker units cost less.
+ Achievements should be described when hovered over - so that you know how to get them for their star values.
+ Rats need a better ability than "slow" if they're going to be useful beyond level 3.
Overall:
The different take on defense games is nice, but so much is lacking in the execution. I wanted to like this, but I couldn't enjoy it beyond the difficulty challenge.
#1 recommendation:
Re-think the core concept of the game. You have three groups of units - perhaps re-configure it so that the game is about mixing and matching units based on the player's personal style rather than gaining more powerful defense units. That would add replayability. Otherwise, at least ensure better balance and scalability while eliminating grinding difficulty.
Like I said, I enjoyed the challenge, but that was mostly because I got creative with the exploits. Most people will find this too difficult and bland, and won't spend the time trying new versions.