The longest I stuck with the franchise was through Metroid Prime Hunters for the DS, and it wasn't the graphics or the game itself that captivated me (although both are awesome, ngl) but the online capabilities and gameplay, I have not even finished the game, only played several minutes of the campaign (which maybe I am not missing out of much here, as I have read it is one of the weakest), and yet I have had more than 500 hrs of playtime thanks to the multiplayer, which I still used even after the closure of the servers thanks to Wiimmfi.
For me the gameplay with the stylus as the main aim control is the best the DS can offer to have a proper and fast paced aim, if you could search for some of the crazy stuff that the pro players managed with this game on YT and how hardcore it can get for this hardware in those days, you'd be surprised, here is a video that comes at the top of my mind, and it is a recent one too, also the sniper battles (imperialist) were pretty awesome.
With that said, I know the franchise and what it means for everyone, I appreciate it that much that I refuse to even play more metroidvanias without finishing Super Metroid (and Castlevania Symphony of The Night while we are at it).
Ahh, this is me with Toy Story 2 for PS1... I have yet to try the dream cast version!