Complex sentence: Chris Crawford states in his book "Chris Crawford on Game Design" that it was the first ever platform game; however, it differs from most platform games in that the character cannot jump over any of the pitfalls.
Split into simpler sentences: Chris Crawford states in his book "Chris Crawford on Game Design" that it was the first ever platform game. While it is considered to be the first platform game, the character cannot jump over any of the pitfalls.