I never did figure out what to call this thing.
I saw this interesting game that Kazufox made, and it got me inspired to try something similar. I was curious to see if I could create a platformer too. I also badly wanted to see Samus shooting goombas. I managed to throw together a running demo in just a few days. I then spent a couple of months adding many features and some levels.
I gave the characters quite a few different moves. For instance, Peach has a Megaman-style power slide, and the ability to float. Samus has all her usual moves, as well as some improvements. Her booster jump can be triggered from a wall-jump, and go in any direction!
I also maintained a development journal so people could see how I approached the creation of this game. This project was started before I created my Universal Level-Editor. But I later adapted it to use it.