The first time I ever played Prime I went in expecting it to be like Halo and was severely disappointed by how slow it was. I'd never played a Metroidvania before and I just didn't "get it".
Years later I revisited it with adjusted expectations and more of an open mind, and now I consider it one of the best games of all time.
Prime 4 has some big shoes to fill, as the first three entries are all fantastic, but I'm optimistic that Retro can deliver; what they've shown here is incredibly promising, and they have yet to release a game that's not excellent.