Simply wow...
I want to start of by saying that this is completely amazing and that fully deserve to be in the tower defense game. I'm sure that if you do make it, you'll get to be one of the final difficult songs due to the intricacy of it.
Now onto actually song critique! Aw who am I kidding? This song is nothing less than complete awesomeness! You really boosted the quality and intensity of the song since I last heard it. I'm glad you added the things you did. It sounded very nice to begin with but you really made it far better somehow. The bass is deeper, the guitar is cleaner, the singing is more blended with the music and so on.
I like the ending that you added to it too. It ties the song together much better, giving it a much less abrupt finish. The whole song, while greatly fluctuating in intensities, flowed really well from beginning to end.
Another thing I really enjoyed was how different it sounded depending on the speakers that I used. I switched from mid sized speakers, to a mini speaker, to headphones, and even to a guitar amp and with each I could hear different sounds and subtleties. While the quality was drastically different with each, they all sounded equally amazing.
If I have any complaints, it's about the "sharpness" of the song. I keep wanting to turn the song up louder but when I do, it tends to stab my eardrums. Some things were just a little too high pitched or have a bad resonance with me or something like that.
Anyways, I wish you luck on winning the contest to get into the game. And as usual, I can't wait to hear your next masterpiece. Merlin is a wizarding name after all, so never stop working that musical magic of yours.
Your everloving fan,
~iHaruhi