I'd say that's waaaay too generic to guess. Elaborate a little.
Welll my idea was to make a main character with various sprite animations and a few keys simply control all of this... essentially the game adds an unpredictability since the game controls how the character lands and such. This is nothing new but it's just different when you have several different ways of landing, depending on the motion the character takes based on how the game computes the character's "motion-taking".
For example, in a normal platform game, you generally don't have to worry about a consequence to the main character hitting the side of a solid object at full speed (or close to full speed). But in this, the player could potentially fall over from smacking the wall. Or perhaps they will keep their balance. There's the slight unpredictability that can come in.
There may also be a bit more of a unpredictability than this... such as a bit of a random aspect to the physics.
So essentially you have a platform game with beyond-average physics... and the feature which tries to make the game the most fun, is the physics.
(Essentially, the anatomy of the character sprite can't be too stiff, or movements will be unbelievable.)
However the main concern that I can think of with the whole idea is that it could be interpreted as "sloppy controls". It's hard not to make such a thing appear as a "goof-up" by the developer which they did in trying to create a predictable physics, rather than a legitimate aspect of the game.
*brainstorms* Perhaps the idea would work best if it was manifested in the way of allowing you a "get out of dieing free" reward every once in awhile. Such as instead of the player always dieing when they hit spikes, every once in awhile they're able to bounce off them.