I think that a really nice addition to the game would be if the assistants of each faction had a different small buff that they granted. I.e.: the elves could have a slightly smaller chance of finding faction coins, and so on
Guys, don't kill me because of this, but am I the only one who does not hate amazons? I mean.. They do require some mana management and some good tower positioning, but, for instance, in level 18 I do not use even a single terror spell to clear charm from towers. I just think that Iron Guards are so much more annoying!
SPOILER ALERT
I hate the last boss
Srsly, first of all your towers are TOTALLY useless against it, no matter how strong they are as they simply do not target it.
Secondly you're forced, not only to have a fast reaction and a good mouse aim, but also to have a perfect fps so that there is enough time for you to click all the bombs it launches
Not that I havent liked the other bosses that you had to click items, is just that, unlike the others, you cant let a bomb go unclicked. If you let the bomb explode you cant see if another falls besides it, moreover the effects (and also the high amount of towers and projectiles in last level) lag lower efficiency PCs, making it impossible to carefully manage every step of the game, which means almost certainly that one of the champions spawned is going to touch your gems
I honestly think the game is almost perfect, best of its style and I love the chalenge it offers, but definitely, the last boss screwed the end of it.