Great concept, and a great game overall. The levels were challenging, but not so challenging that they became all too aggravating. Despite the complexity of mirrored characters and forcefields, the controls were always clear and simple, and using them just right was the real challenge, not learning how to use them. The keycards were an extra ladder in the game playability, and the bonus levels a lotta fun. I'm glad they were actually easier than the ones before the first ending, it felt like they were just... fun. :) Looking forward to the seuqle!