Yay! More Door song! Also, TD6 is such an awesome nickname. It's both letters and a number!
I actually really like this song (well, apart from that one bit at 1:40-1:44). The intro sounds really good. I don't really think the instruments were EQ'd badly. Apart from a slight issue with the density of the tracks (not enough), they sounded great. Also, that drum beat is one of the best hi-hat/white noise patterns I've ever heard. Most drum beats just have really straightforwards 8ths, but this was a great change.
When the piano re-enters at 1:48, I think you definitely could've made the bassline different. The piano melody is really good; sadly, the bass on my headphones is really loud and I don't think the chord progression really worked. Once it gets to 2:28, the song gets all awesome again. I think the use of semitones really contributed to the eerie feeling, but towards the last ten seconds-ish, I think you began overusing them. :P I loved the way you ended it, though.
Since the song is called "Shadows", I wouldn't have minded a bit more reverb and maybe some pads. I think a bit more density would be a great idea, but this song is pretty awesome as it is. I don't think you need to change the melodies, just change the bass, since a few of the chords are a bit off.
Great job! Hoping to hear more from you (although maybe not, because of the dreaded May exams and you being in junior year and all that)!