I'll put some of my input.
X1: Awesome start for the series, I loved the darker plotline and Zero's death scene. Music was great - even the non-fan-favorite themes kick ass.
X2: Very nice expansion of the first game, better levels, music still rocks. The side quest for Zero is neat, too, even though the side battles are a bit annoying.
X3: This one SUCKS. It's not worthy of "SUCKS", but it's mediocre. It lacks emotion, level design is boring, art is uninspired, the music is awful (minus gravity beetle). The Ride Armors were nice, and I liked how the bosses later on change depending on how did you beat Bit and Byte.
X4: Oh bloody hell, I love this one. I don't know exactly why - maybe it's the weapons, maybe it's the levels, maybe it's the kickass armor. No, wait, it's because of Zero, but the rest adds a lot, too.
X5: I like how the plotline twists depending on what you do. It's got nice music, very good level design, and letting you switch between X and Zero was really nice.
However the time limit was annoying. And Dynamo. Oh man, FUCK DYNAMO.
Although I kinda like X6, it might've been better if the series ended here. Would have been a glorious end.
X6: Pros: Absolute best soundtrack on the X series, bar none. Maybe even in all of Mega Man. The art deserves a lot of praise. Myself, I like the bosses here (particularly Heatnix).
Cons: Level design at it's absolute WORST. Pits, pits, pits!!
WHO THE FUCK CODED SENTSUIZAN TO SEND ME DOWNWARDS WHEN I PRESS UP!?! WHOEVER YOU ARE, OUT THERE, FUCK YOU!!
X7: This one isn't as bad as most people make it out to be. Unlocking X sucks but Axl plays quite well. The soundtrack is the worst on the whole series, the model characters do look grainy (even with component cables....), but it still manages to be worthy of the Mega Man title.
What sucks most about X7 is that at first you have to play through the levels many times to get upgrades (because of how underpowered are the player characters).
X8 is waiting until I finish X7.
Maverick Hunter X was an A-grade remake. The only thing that it would have needed would've been Zero as a playable character and
Spoiler warning:
I can't even recall the GBC games.
That's all there is... no?
