This is actually built in Retro Puzzle Maker by NES developer ChrisCCP, although I did heavily alter it afterwards with my own code to do things like add extra characters and stage designs not available in the original project. I'll probably come back to it this summer and flesh it out further, but I'm currently working on a much more ambitious visual novel sequel which has a demo available here:
https://destroyed4com4t.itch.io/senseless-city-space-jesus
Glad you liked it!