Challenging at first, but you get used to it. That is, until they pull some really twisted deviant stuff that you have to figure out just when you think you got used to everything. I first experienced Metroid through a used copy of Prime 1 on GCN I got for my 11th birthday. The thing was only 3 bucks, a damn steal if I ever saw one. Look up Prime's costs today and you'll be busting out almost triple digits sometimes.Never played a Metroid game. are they really hard? i kinda suck at games despite playing for years and stuff like dark souls make me want to cry.
Though I might pick up Prime 4.
You could also just get the Prime trilogy from the Wii U E-Shop I think, but I don't have a Wii U so don't quote me on that.