There was a WIP made of the SNES version a long time ago. It plays back on the "snes9x-1.43-improvement15.3-win32" version of SNES9x which you can find in the emulators section.
This is the topic with WIPs in it:
http://tasvideos.org/forum/viewtopic.php?t=5145
I think there was also another topic but I cannot find it right now.
I am not certain though but I think it was decided at some point that the SNES version was the one preferred for this game. (You may want to verify this before you begin if you want to have the TAS published here. It would suck to have it rejected for using the wrong version)
Here are a couple of the easiest tricks that work in the SNES version at least (since this is the only version I have played):
* Olaf and Erik will make a great duo when it comes to shortcuts.
* Erik can use his dash without running by jumping first and pressing dash as he lands.
* When falling great distances it's a good idea to take damage from the environment or enemies before landing (but not too early) when possible as it will reset the distance you have fallen, this will skip the crashed-into-the-ground animation.
Another tip is to make (or find) maps of each level and noting where you find all the items you need. No matter how well you know the game, looking at a map may help you find possible shortcuts you didn't think of before.
There is no version of this game that offers 3 player like there was on the first game (Genesis version). So you're limited to 2 players, there can (and most likely will) show up situations where you can switch rapidly enough between 2 characters that it will seem like a 3 player run, however, don't do this with normal walking as letting Erik dash ahead and follow with the others is almost always the fastest way of moving.
Good luck!