Generations I skipped. My last sonic game before frontiers was sonic adventure 2. And that one where you're a werehog...don't remember the name. You're really missing out not having played frontiers. It's really beautiful and it's all open world but with classic sonic levels in cyberspaceI've always wanted to try frontiers.
I don't have any very modern consoles, my only one is a PS3, so I'm stuck with most of the old games. On the other hand, I've watched the play-through and cutscenes for almost every game.
I'm super excited for the next movie.
Have you ever played Generations?