29th November 2004, 1:26 PM
The collecting of the keys was a bit odd, since the previous Metroid games never had anything like that. I thought, however, that it added to the overall difficulty of the game by forcing you to scour the light world for new portals and the dark world for the keys. Also, the progression was certainly different from the previous titles, but I didn't really think it hurt the game overall.
Sometimes you get the scorpion.