Love the narrative approach this one has. Working your way from isolation from the earlier prime games and actually working directly with the federation force in the 3rd prime installment is a breath of fresh air.
The environments are a bit too tunnely and and a bit of a step down from the lavishily detailed environment in prime 2. Loading segments gets really in your face as you take shortcuts throughout the latter half of the game and valhalla is outright filler with lots of load times as you try to speed through. despite some of it's quirky design approaches, it's still a solid metroid with very intuitive mechanics.