Samus' last adventure is certainly not a silent one
Metroid Fusion is chronologically the last Metroid game(the Metroid Prime franchise takes place between Metroid 1/Zero Mission and Metroid II: The Return of Samus), and it's Samus' first 32bit adventure on the Advance.
Personally, I really enjoyed the game throughout. There were some things I disliked about it but generally the whole experience is very enjoyable.
Samus' new abilities, such as climbing ladders and the Power Grip which allows her to grip ledges come in handy for sure. I also like that they made the missiles upgradeable, that really simplified a lot of things for sure. Overall, Metroid Fusion feels simple, easy to play, and something you can just pick up and play, which is how handheld games should be like.
The sound effects are very well done in comparison to older games.
I didn't quite like the fact I couldn't skip the cutscenes. Having to watch the long intro every time I start a new game is a real pain in the butt.
Also, I didn't like how much the game relied on story and mission objectives. I felt that the freedom and non-linear experience I had in Super Metroid was completely absent.
Also, the music isn't nearly as memorable as the Super Metroid soundtrack, but it fits the atmosphere well.
The Bottom Line
Metroid Fusion is a game that some will find very entertaining and exciting, with huge replay value as you will try to find more and more items and do it with less playtime, while others might find the increased linear story-driven gameplay boring and uncharacteristic for the series in general.
But all in all, Metroid Fusion is not a bad game. It's maybe not the best in the series(I give Super Metroid that title), but it's playable, and it gives room for another prequel.