As long as you set up the camera correctly you can do it. It's not designed for it, but it can be made to work relatively easily.
I'm not talking about just setting up the camera. It has some kind of issue with subpixel movement and textures, I don't remember the specifics. This was a while back, so maybe it's been fixed already.
No, that's the point. If you set up the camera correctly (and set positions using integer values only, and budge the pivot point by half a pixel in both X and Y so it sits on a pixel rather than between them) those problems go away. Setting up the camera is the biggest part of that, really.
That is what I did, and I still ran into sub-pixel issues. I know exactly what you're talking about. That's why I said that maybe it's been fixed already, because I was doing this a while ago.
Regarding Clickteam Fusion 2, has anyone considered maybe converting Sonic Worlds to this? http://mp2.dk/chowdren/ I mean, Worlds is already open source, so using this and releasing that source wouldn't actually be that big of a deal. The only issue then is how to handle level creation, but all somebody would have to do is build their own level editor that plugs in to the Chowdren Open Source Sonic Worlds
It might sound worthwhile on the surface, but consider how that would work out. At that point, you might as well write your own Sonic engine from scratch in C++. If you convert Worlds to C++, then you're stuck with the engine exactly as it is, or you're coding it with MMF2 which still carries all its limitations, or you're writing code in C++ while trying to cooperate with whatever messy conversion is rendered from the MMF2 project. There's no middleground and either way you do it has huge compromises. This is only really useful for a game that's already been finished with MMF2. Making a new Sonic engine in C++ would have the potential to be cleaner, more efficient and more flexible. Level building is not really the issue here.
Technically, it has been converted. See: Freedom Planet However it requires a LOT of work and actual money to do it, and the end result will be... difficult to implement new objects and modes into. You'd be better off sticking with MMF2's editor, or use HCGE if you want a multiplatform C-based Sonic engine to hack on.
Well, I mean, it cost Freedom Planet money because they're a commercial project. For non-commercial projects, I think it's just GPL.
No, it cost Galaxy Trail money because they had to port the extensions used, on top of being a commercial project. If Worlds Delta were to be ported over, I would need to shell out money for the extension porting. And it STILL leaves the problem of creating an engine that cannot be easily edited.
Which... I already covered in my post above. It's not a good solution because there's no reasonable middleground. Either you're better off using MMF2 start to finish or developing an engine from scratch in C++.