Originally Posted by Eternal Man [EE] I personally dislike polymorphic tweening, I think it contrasts too much with the rest of the gfx (if you are making pixel gfx that is).
That has to do with your particular art style, not the technique itself. Like I said, the technique is basically deforming various shapes, and it can work for any art style. For instance, my christmas compo project balances this perfectly. If you wanted to go for a more pixel gfx style, you certainly could.
@Gamester: I don't know of any tutorials online anywhere, although I'm sure they'll have them. Since it's one of those techniques that isn't talked about much, almost forgotten, it doesn't really get around. I personally learned it from a good friend of mine, who's a college educated artist/animator. I might do a tutorial on it, but he's really good at explaining things, so I'll see if he'll be interested in doing a few tutorials.
Will be interesting to see your game!
And as a conclusion: Use the technique that suits you.