Home stretch! Thanks to some help from folks in Discord, switched to composing music assets using BeepBox.co (was having problems with Deflemask's exports, unfortunately).
Level 1 designed, Level 2 in process. All deadly hazards implemented, though still need to add moving platforms / disintegrating platforms.
Weird glitch encountered where anything using the text box code in the same room as another thing using the text box code is triggered as if they're the same thing? Too tired to figure it out right now.
Tomorrow, hoping to finish up level designs for all 5 "exploring" levels and the home / central screen, as well as output a couple more musical themes so each zone has a unique one.
Some screenshots below; not currently using a tileset on the background (just doing color), but if I have time I'd like to try to make one, especially after seeing some of the great BG art others have been using here!