I think that I never want to play a linear platformer again where you have to guess which way to go off the beaten path to get some collectables and face constant anxiety that you missed one and you're gonna have to replay the level again from the beginning to find it. WE CAN DO BETTER
I've had this sort of platonic ideal of what my favorite kind of sidescrolling experience would be in my head for years. I was trying to make levels like this when I was actively making a sidescroller (and before I got burnt out on it). Levels that would loop around on themselves, have several different layers. The player going in these cycles hitting triggers that would eventually complete the level. Exploring and finding collectables wouldn't feel like a binary or miss-able experience like in a left-to-right game. It's got elements of a metroidvania, sure, but I like the idea of a series of small, self-contained spaces like this. I also like the idea of the level changing in certain ways as you hit triggers, opening up and stuff.
For example this was my concept for the first level which I only half-finished. Climb up and go around to release the water, it destroys the block of dirt at the beginning, you drop down and then climb this big vine that grows from the water. Fun concept to me!!!