Righty-o, review time. Keep in mind that when judging (or thinking in terms of being a judge), I tend to be harsher in terms of scoring.
The Good:
-Nice instruments, even if some of them are fairly standard fare (like the pad). Great little ear candy percussion sounds, first come in at 0:47. Also, excellent percussive instrument playing broken chords around the 1:45 mark.
-Cute little melody.
-Nice little break in the percussion at places like 1:08 and 2:39.
The Not-So-Good:
-First, yes. It is a generic chord progression. This wouldn't be so much of an issue, but it never changes - what this really needs in terms of chords is having some section where they do something different. Keeping the chord progression the same will make the piece sound monotonous, and quite honestly boring. At the very least, try changing the notes that you're using to form the chord. You can use inversions, or you could try some more open sounds by only using two notes. That would also let you experiment with changing the scale even within the chord.
-Second, melodic content. You have the main melody, and an arpeggio which *could* be called a harmonic line, but it only does the chord. Try having a countermelody, even if it's not there the first time you play the melody. At around 2:39, you could easily have a second melody playing - this would add a lot more to the composition.
-Third, mixing. This is good in that it doesn't clip, but there's certainly some mud. You have the original arpeggios and plucks in the first 45 seconds, but after that, the plucks and arpeggio are buried under the other instruments, despite playing the same pattern. Try using panning more liberally and spreading the frequencies out. This does not improve in the second half, when you have the other instrument playing broken chords on top of the already-existing problems. This does also affect one of the ear candy percussion noises :( The little "bwob" sound is buried almost entirely in the second half, where it's actually audible (barely) in the first half.
-Finally, transitions. Intro is acceptable, though it could certainly be better. Other transitions are fine, if a bit generic. The ending is basically just bad, unfortunately - it sounds lazy, like you couldn't be bothered to conclude the piece. Basic rule of thumb which I use for endings is that they shouldn't just fade out without some kind of conclusion, and they should never ever ever just let a pattern end. At the very least, have a chord that the piece resolves to. If you want, I have a news post which explains transitions (including intros and outros). http://skyewint.newgrounds.com/news/post/857638 This might help.
Overall: The composition of the piece is a serious weak point. The mixing is decent, though more clarity would have been helpful. The ending... well, endings are somewhat of a pet peeve of mine, but the ending definitely needs an overhaul. Hopefully this helps explain why the judges decided what they did.