For a first chiptune song, this is pretty nice. First impressions after hearing it were: It's got nice melodies and sound effects, but needs more depth.
When I say depth, I mean that you could possibly add more sustained notes. It seems very spacious right now, since you don't really have any instruments that are playing through each bar, just a bunch of instruments that play really short notes, nothing longer. Not saying that this is a bad thing, but it does make listening to it a little more confusing and jagged-y (if you can understand what that means).
I also think your drum noises could use a bit of work. While the other instruments are pretty good, your drums lack the 8-bit-ish quality that makes chiptune to endearing to so many people. I think there's an effect you can add to them called 'Bitcrusher' (not sure exactly how FL works). Even if it's not called 'Bitcrusher', there's a method of making things sound more 8-bit in most music-making softwares. I think.
Onto the good stuff! I think your melodies were great. They were a little spread out, but a few of them really stuck in my head. Funnily enough, the catchiest one for me was the base melody that kept repeating, maybe because it didn't just appear in one place; it stayed for the remainder of the song. I think the essence to a catchy melody is one that people enjoy and isn't blasted in people's faces, but one that appears pretty prevalently through a song so that people are satisfied with it.
My favorite part of this song was the effects you used. For instance, the 'broken' white noise sweeps. I loved that. In fact, i didn't even notice that it was happening so often until a replay, when I heard them a lot more. If you can do quarter breaks in them, why not try eighth breaks? Sixteenth breaks? Cool stuff like that really captures an audience. Also, there were the background effects that sounded great with the song, the little blips and boops. And that little detail you had at the end of the melody at 2:54 was unexpected but hit home as well.
Anyways, good job on your first chiptune song! Obviously, it wouldn't be perfect, but it's still really good. Looking forward to seeing more stuff from you, TheDoor!