This one just looks great the art direction and animation give it that early Diablo look, the game play is that "try, try again" model but being able to shuffle your army's units to suit the upcoming enemy is a useful tool. Though in later stages your weaker units become redundant and the enemy list is always the same which makes it predictable.
Though the Demon makes for an "ok" tank unit he seemed pretty underpowered considering how expensive he is; his one special move is really not all that impressive, given the (comparatively) short cool down time it has. On a side note when facing the Titan he resembles a marching band leader in his underwear.
I think randomly spawning enemies could really take advantage of the unit shuffle. Everything that's good about this game is really good, the bad are just minor nit picks. A sequel would be awesome! :)