My thoughts...
This is an awesome idea
I actually thought of doing something like this myself once, but due to lack of time etc I never got around to it. But yeah, I've always wanted to be able to make Abe's Oddysee/Exoddus levels, so this is a pretty good thing to see. Of course, it needs a lot of work, but it's looking very promising!
As for the slog-possession thing you mentioned in your other thread, I think if you want to add features like that you should make it so they can be turned on or off in each particular level if possible; that way, if people don't like the idea they can turn it off in their level or vice versa.
Good luck, and keep up the good work!