some kind of abstract experimental music I was playing with... https://soundcloud.com/cris_camp/somethingnew

You use pauses and silence well.  Nice use of your complete palette of dynamics.  Were you intentionally going for synth sounds?  If so this is fine as it is.  If you wanted to translate to a more monumental sound with a real orchestra (some of the brass for instance)  it would sound fantastic scored for an orchestra (or orchestral samples).
 
Also, you could add a little variation in the piano velocities unless you wanted a more straight-ahead invention-like sound.  It all comes down to what your intentions are versus how it comes across.

 I made this song Saturday morning and I didn't really spent much time in making it sound perfect. I think I have like 5 "instruments" on it  and probably the one in TTS sounds a little artificial but I didn't aim for synth sound. This was more like an exercise... I'm glad you like it !

Well, it's the ideas that are important.  Orchestration and production can be taught! :D:D