X5 is a great entry, though some pointless stuff ruins it from ranking with the top dogs in the franchise.
Finding stuff is more annoying than usual, and some require you revisiting stages 2-3 times to get everything, finding armors are a pain and once you finally do get them, they are lame as hell, okay, the flying ability with the Falcon armor is pretty cool, too bad the buster sucks which fires a too small energy blast. The armors are also absolutely necessary to get some of the heart tanks, and that's the only thing they're good for. Another thing I didn't like was that the bosses you have to face once more towards the end are at level 96, first of all, it takes too long to kill them, second, that's the same level as Sigma, shouldn't he be...I don't know, way more powerful, he is, absolutely, and it's just a number, but do it like Dragon Ball, have the meter say some insanely high power level which makes it more impressive. The bosses are really cool, named after people involved in Guns n' Roses and they look awesome and unique, save for maybe one, no, not the whale, I think he rocks. The gameplay is almost as much fun as X4 and the difficulty is nicely balanced as well, the only frustrating parts are the ones where you have to find the Light capsules. I wish the game would have cutscenes instead of still images and text, but fine, don't have to deal with awful voice acting then. I really enjoyed X5 despite the flaws, which don't ruin the game in any way, they just keep it from being one of my all time favorite MM games.