Absolutely terrific game, Have been playing for 5 hours straight.
-Few suggestions, Maybe adding in a 'final wave' or have a wave tally E.G. 1 / 50. (Hate having full inventory of weapons and stage ends.)
-when you finish a level, maybe go straight to the level screen instead of main.
-If you get 2 full rows of something on the farming screen (can be different) get a bonus of some kind (people will try harder to save mats for bigger combo gain)
-For when inserting gems, be good if you could highlight a tower, then double click on the gem for auto input.
-When you get a row of something in the farming screen, be good if a little number popped up showing how much you gained.
-When equipping items, where the stats are for the new armor (unequipped) it shows underneath what you already have equipped.
-Maybe gems for the hero too?
I hope any of this has helped.
This really is a good concept for a game, I hope you make more games in the future.
5*
 "BattleCry"){kind=icon}
 "Elements"){kind=icon}
 "World of Warcraft: Blood Elf Dress Up"){kind=icon}
 "Miscrits"){kind=icon}
 "Glissaria"){kind=icon}
 "Onslaught2"){kind=icon}
 "Get Mad! feat. \"Rage Guy\""){kind=icon}
 "Mushroom Revolution"){kind=icon}