I know there are obviously other things that you want to do first, Ash, and there is a lot on that to-do list, but I do feel the need to point this out.
The platform behavior is neat, but the Classic behavior has some things that the C2 version doesn't:
- Variable jumping height
- Air speed options
- Inverse control
- Bunny hopping option
- Being able to fall through platforms (would be nice to be able to do it with a custom key, too)
But I also think that the behavior has some other limitations that could be addressed that limits what people can do with it. Namely, rotations. Some platformers (Sonic being one of the first examples) allow platforming characters to rotate on slopes, walk/run on walls, that sort of thing.
I've tried to do such things with the custom movement, but I'm pretty sure it's extremely difficult to do, because methods from Classic don't work very well at all. Physics... Just as difficult, if not moreso. And the only other alternative is making your own movement through pure events, and that can get very complex indeed (especially if you're trying to create something momentum-based like Sonic).
I think it might be beneficial to create an "Advanced Platform Behavior" that gives users much more flexibility and options on how they want to make a platform character to move. Do they want rotations on slopes, or not? How about being able to slide or roll down a slope to pick up speed? Stick to walls and ceilings, or fall off if there's not enough speed? That sort of thing.
It would unshackle more than a few of the limitations of the behavior while also giving users the option to start off with the "basic" version, and moving on to the more advanced options if they want them. Slope rotations, believe it or not, would go along way to extending what a platform character can do.
With that in mind, I imagine an "Advanced Platform Behavior" (or just an improved regular behavior) would have these features:
- Slope Rotations
- Slope acceleration/deceleration
- Collisions based on objects/families as well as the Solid/Jump-Thru behaviors
- Toggling collisions with particular 'solid' objects on a per-instance basis (rather than turning off the actual solid itself)
- Some other stuff I can't be arsed to think of right now
Long story short, if you can faithfully recreate Sonic platform physics using such a behavior, I would say that would be the point where you can say 'mission accomplished'. Can't be that hard, surely. :)
I know there's a LOT on your plate, but I guess it really can't hurt to make suggestions.