felix - i want to hear your writing in a little bit longer form. here and in the previous piece you posted, they both sound like very interesting introductions where the real meat of what you would be communicating would come after. in others words, what i'm getting here is, "okay folks, here it comes!!!!!!" ... then it ends just as i can tell you have something interesting to say (i hope this reads like the compliment it is).
as far as this piece, the detached articulation of the trumpet at it's peak seemed melodramatic and almost humorous. but i think it pointed to something i heard in your previous piece that could be constructively addressed. when a (good) player hits a note, they will do something with it because music isn't about the notes. you're already very good with the actual dynamics of a line, yet because the notes are a little static, the line is not coming acrosss dynamically - meaning the actual volume levels are great, but the notes themselves could use a little shading. while this could mean more rhythmic variation in the line as we talked about before, that could change your composition style which might not be a good idea. perhaps just opening up the phrasing a little and using layers or filters to shade the individual notes as they are happening would help. just remember, if you're "just" hitting a note somewhere without doing anything with it, it will combine with other such notes in a cumulative effect and bleed some life from your music. the opposite will breathe life into it.
i really enjoyed the tonal change similarly because it added interest. it kind of broke a rule that suggests not to introduce new ideas right at the end of a piece, so even as i didn't like how it resolved, looking at it as preparitory material for a longer piece seems fine, even refreshing. so if you're up for a little harmony excercise in a cinematic style, you might try something maybe over the course of a minute or two where the harmony is constantly changing but limited to movements of either a third, sixth or tritone. you don't need to read music to understand this so don't let it daunt you. just move the chords in either direction up or down a third (e.g. c to e; major third, or c to e flat; minor third), a sixth (e.g. c-a; major 6th, or c-a flat; minor 6th) or by tritone (e.g. c-f sharp). use any combination and the actual chords can be major or minor (like a c minor chord going to an e flat major chord, etc.). you might find yourself in some strange keys but that's just part of the fun because your ears will force you to make music out of it. the idea is to have a vehicle to move beyond a single tonality without bringing things to a cadence before you're ready. hope this helps.