Which ones did you like?
At the risk of adding spoilers: The Queen Metroid and Phantoon were my favorites. I believe there was at least one more that I liked, but I don't remember. I found the Ridley fight to be uninteresting. After so many excellent battles with him in the Prime trilogy, there wasn't much they could do to top them.
That construction/heavy machine equipment battle was the worst one. Ridiculous battle. Big machine like a freakin loader dombined with a bulldozer, but it moved like lightning and could turn on a dime. Fucking obnoxious battle sequence.
But the Metroid fanboy in me was just giddy as hell when the Queen and Phantoon entered the fray. I only wish the rest of the damn game lived up to the joy of those two battles.
I think the Phantoon battle was my favorite too. Even if it was just 5 or 10 minutes of spamming the Sense Move and charged shots.
I'm guessing you didn't play hard mode, correct?
No, I shut it off, fuming with rage, and never played it again. I almost didn't play it after finishing the main story. But I forced myself to see if there was any redeeming value after the main part was finished.
But then, I rarely play through a game more than once these days. There's just so much to play and I want to experience as much of it as possible. It's shameful how many games I haven't finished. I only finished two recently--Steel Diver and Batman: Arkham Asylum.