This game needs a severe rebalance. It's extremely easy to win merely by investing a bit in ranged attack and making an elf deathblob with a few healers thrown in just for fun.
Finished the storyline, voted 3/5. Haven't tried survival, but game was too easy - found 1 strategy, stuck with it all levels, then last boss was a disappointment. Still a fun twist on TDs that i haven't seen too many times.
Suggestions: Toughen up the levels significantly, change enemy abilities and stats somewhat (the only challenge is the ghost, and barely one at that), add a horizontal fire-through block, then give the shop some actually interesting upgrades - these are way too boring. Dad could use some retooling too, since essentially i could have had him stand still halfway through every level and it would make absolutely no difference.
Overall, though, nice concept, so-so execution. I've seen you do better, but there's a whole lotta' worse out there.