Guessed by @UnderwaterFunktown
It's funny to think this game was once seen as controversial for being "too linear". It makes sense, I suppose, since linearity was seen as the bane of existence back in the day. Yeah, Fusion is linear, and it's all the better for it. This was the first Metroid game to really attempt a more in-depth narrative, and to this day, it's one of very few that actually stuck the landing - I'd argue the only other game in the series to do it right was its 19-year-overdue sequel. And even though it takes its place between two widely acclaimed masterpieces in Super Metroid and Dread, it more than holds its own and stands out as one of the best and most iconic entries in the series.
Moreover, it's genuinely impressive how Fusion manages to change and retcon so much about the earlier titles, without ever coming across as heavy-handed. It makes the Metroid universe so much richer and deeper, and scarier, and it just works. It took what was supposed to be a self-contained trilogy, and turned it into a longer series without ever feeling out of place. It's not every day someone makes a good sequel to a finished story - and more than just a good sequel, Metroid Fusion feels essential. And while it left us on a bit of a cliffhanger for what felt like eternity, that cliffhanger led to an even more amazing game. I'm so glad this was made.