Oh, you made a whole soundtrack, that's impressive! I really like the mood of it all. I agree with anipatok's comment regargind the similarity of the track and Error404 about the melodies. One trick to fix both problems could be using a leitmotif. So you can make a melody that will remain in the listener's head and use it in tracks that are different in mood, tempo, instruments, etc. but remain recognizable as part of the same environment. Keep going like this!