You didn't lie when you put "A very difficult" in the description.
I have to agree with other commenters, that E button for swap wasn't the best call, although after a while I didn't have that much problem with it, you often use E in FPS games after all.
The game is exactly what it promieses and utilizes a role swap or even a world swap I would say to its fullest in terms for the mechanics. Of Course the graphics are simple and ms-paint like (probably even just made in mspaint) but they got a charm to them, and I will be 100% I wouldn't be able to draw that myself, even if I spent the whole 48 hours on it :P
Good job