The terrain isn't beautiful, really.
You spammed cinematic doodads (all kinds of fire, energy field) and everyone knows (or should know) that cinematic doodads are ugly, especially when spammed.
The tileset is just another 'look I can create patterns on the ground'-type of tileset, the creep move along a blizzard cliff'ed wall on a monotone path.
The triggers are extremely inefficient and leak (according to my own rules, spawn-based maps such as TD's aren't allowed to leak or they will get rejected).
And well, since you should abide by my rules: you must fix this in order to get your map approved (and even if you fix this, you've got to fix a lot of other things as well).
Apparantly you don't really know what to do with the "Damage Number Sides per die/Number of dice", as they're all left standard.
Learn how the damage formula works, it can greatly improve your work.
The tooltips also need some major improvements: you should create an easy to read tooltip template and use it for all your towers.
The hotkeys sometimes override eachother (sky/ground destroyer both have D as hotkey).
The only good thing I noticed about the objects is that you put them all in the same race.
I do like Pendulum (Hold Your Colour is a better album imo though), but the music is absolutely not necessary.
If I want to listen to Pendulum, I'll listen to iTunes (which I would do either way), there is no need to import this song: it only fucks up the file size.
Remove it...
The gameplay looks like just another TD, aside from some 'secrets' then, but honestly: they can be seen in other TD's, such as Achievement and Snake TD as well.
All quests have the same icon as well (a very basic mistake).