Actually, I’m going to save you some time and identify which segments go with which song and which segments are their own.
Song 1: 0:00 - 0:02
Song 2 part 1: 0:02 - 0:09
Song 2 part 2: 0:09 - 0:13 (Make part 1 of this song first, then have a silence transition to this part)
Song 3 part 1: 0:13 - 0:17 (Do a similar thing with this one as I said to do with song 2)
Song 3 part 2: 0:17 - 0:37 (needs to be smoother and the notes need to be held longer)
Song 4: 0:38 - 0:53 (Scale down a bit more or have more of an intermission between notes)
Song 5: 0:54 - 0:59 (This one needs some work or can be forgotten entirely)
Song 6: 0:59 - 1:14 (This one is great, but needs more note fade, or a longer rest between notes)
Song 7: 1:15 - 1:23 (Great already, just make it into a full song.)
The end has some good stuff in it too. You just need to chop it up and add it to the other song segments in this list.
Overall, you have potential. Segment 7 was your best. I’m not sure why you compiled all of your completely different song ideas into one mp3 file, but you have some good stuff to start full songs in there. Keep practicing. Work on these segments individually and you will have 7 good synth songs.