The main problem with this game is that it takes too long for things to get strategic.
There are a lot of people complaining, and ALMOST rightly so, that there is no strategy instead just luck. But this isn't true, due to the fact that without proper care and strategy you simply cannot beat the game. However, it IS true until about day 30 (or so I don't remember, but quite late nevertheless) where you are suddenly hit by a wall. 'This counters this but may be put to better use here, but wait, I have to time it so this ability is ready for this wave, is it worth my demon taking damage here? Why the fack does the meteor ability last so dam long?' and other thoughts crossed my mind while replacing 'wow this cannot be the game *continues to farm and slowly upgrade units with no real thought process*' quite suddenly and late into the game.
But if a player manages to drudge through the early stages, I think they may find a bit of challenge and enjoyment out of this, because at the end of the day it really isn't a super easy game to beat.
I really did like the art and animations, however I had the sound muted so I can't comment on that.
The UI and info section isn't the best, I found it a little disorganised and inaccessible and while info was easy to find, it lacked a few pieces. It confused me for a long while as to the purpose of the charge button... I wasn't sure if we got an offencive bonus or defencive debuff or ANYTHING. I failed to see a point considering the fights were simply winnable or not until much later, where it was far more useful to delay a little bit. Also it bothered me that rate of fire and actual numbers pertaining to abilities, such as cooldowns and lengths were not put into the info section, I mean, while they are described fairly well (the underworld fighters is clear but at first I wasn't sure if it resurrected them or they had to die while active, or if the demons ability was single target or AOE), I like to actually know the numbers, but I digress, I am quite finicky with UIs and info and I seldom see ones I like, one that really feels easy to read, is organised and easily accessed yet detailed and non intrusive.
But alas, it's a solid game if not a little slow... the 'fast' speed could do with a 'faster' brother option 'cuz there really isn't a lot to do early on in the game.