So completing the cycle I ended up playing Just Platformer 100 thanks to @smbhax ‘s write-up here, which I think he only played because he saw me mention it in the random game topic. The write-up linked still stands so let me just say that despite its incredibly generic name and utterly basic look there’s an hour of solidly done platforming in there. It breaks down to five or so areas each built around a different mechanic but the core remains managing your jumps as you try to reach the next platform up and hence get a newer checkpoint and it manages that very well. There are some occasional bugs and an important mechanic is never even hinted at (although without it you’ll never get beyond the halfway point), it isn’t by any stretch essential but it’s good at what it does, thanks to smbhax for vouching for it!
Hopefully someday… (also let the record show that I finished it in like 54:47, the timer keeps running through the credits >_>)