Is it cheating? Under most people's definitions, probably. But I would argue that this discussion is pointless, and that the entire concept of "cheating" in a single-player video game needs to be eliminated.

Games are about fun, and you should play them in the way you find enjoyable. If that includes what most people would consider "cheating," why does that matter in the slightest? If you're playing a game to follow arbitrary standards in a way that makes the game less fun to you, you're doing it wrong. If using save states makes the game more enjoyable to you, then it is not "cheating" in any legitimate sense of the word.

The only way you can actually cheat in any real way is if the game involves other people, such as with a tournament where everyone agrees to follow certain rules. Violating those rules, then, would be cheating worth condemning. Otherwise, nobody should care.