I really enjoyed playing your game and I think this swapping idea has a lot of potential.
Besides, I'm a sucker for games that use portals in order to progress through levels, and I'm not at all subjective, haha.
The only thing I would have changed was the movement speed, but I know you already got this feedback, I am just adding my 2 cents over an already large pile of coins. :P
In any case, nice job!