An excellent game by many standards
Music and graphics are excellent, but the game play is slightly lacking:
1-The enemy waves are fixed making it predictable and repetitive
(I would suggest adding a random modifier to choose the level and number of advanced units per wave, also this could make the game scale up with the gamer rather than having to fight through the same waves over and over again, especially when they're much weaker than you)
2-What if i don't want to use goblins, what if i prefer to send 40 skeleton warriors rather than 20 warriors, 20 goblins
(It would be nicer if we had full control over the army, with an army size limit, or skill limit, goblins are only truly useful in the first few waves then they die immediately, maybe expand the legion size upgrade and give the option to manually fill legions, which can add the option of mixing units such as using Underworld fighters and Werewolves in the same legion to counter most opposition)
I overall this is a great game, but I'm only giving you 4.5 due to the feeling of repetition