DzNutsKong
2006
Horribly unbalanced game and I don't think it pulls off the Metroidvania style that well. Keeps the combo system from the Zero series which is super fun for ZX and HX especially and OX's inclusion is cool too.
2004
Completely fixes the screen zoom issue, the plot here gets better here than either of its predecessors ever do, and the Recoil Rod is one of the most fun weapons I've used in any game. The combo system against bosses is super fun. Strong contender for my favorite game ever.
2003
I didn't like the Chain Rod but this is otherwise a great beat-em-up platformer with a really nice overarching storyline. Not much else to say.
2002
Very rough around the edges. Level design isn't very good and they make you unlock the attacks in your moveset for some reason, plus the screen crunch really sucks. This series is mostly story-focused and all this game does is set up the rest of the series rather than do anything especially interesting on its own.
2003
Very boring, but an attempt was at least made and it looks pretty without taking assets from its predecessors. There is no reason to play this game.
2001
Playing this game makes me feel like I'm losing my mind.
2000
Not only does Alia stop you from moving way too often, but the level design itself has way more stop-and-go mechanics that just do not suit this series at all. A lot of it feels really derivative from X4 too. This is the first X game I didn't 100% on my first playthrough.
1997
A lot of people would have this as their favorite X game, but I think it's a bit style over substance. The head upgrade is very broken but in the kind of way that makes the game better. It's really easy and I prefer the game feel of the SNES trilogy.
1995
Still solid but a step down from the first two. You take way too much damage from everything and the soundtrack is way too same-y and not very well-composed for the most part. It's fine enough though if you can get past the absurd amount of unnecessary collectibles there are.
1994
My personal favorite X game. The fact that you can 100% the game with no revisits makes it much more fun to replay even if the level design isn't quite as good as the first one. I also have a lot of smaller gripes with the soundtrack. The game's speed and feel are the big draw to any Mega Man X game though and this has that while the rest of the game has less things that feel intrusive towards that than the first one does.
1993
A lot of people will tell you that this is the best game in the X series, and it's very good, but my only two complaints are the early game before you get the leg armor not being fun because you usually play the game for its speed and Spark Mandrill's stage being horrible. Don't use the boss weaknesses in this game or any other X series game because they kind of ruin the experience. Otherwise the game feel and soundtrack here are some of the best of any game I've ever played.
2018
Your more modern Mega Man game. The shop is especially broken in this one and it's a bit short but that's about it. The stages all were really fun and the bosses and minibosses were pretty good too for the most part. The Double Gear system is a great way to get people acquainted with the more difficult gameplay while also not being super intrusive for people who don't use it.
2010
I don't think it's as good as Mega Man 9 but it's not big enough of a difference for me to care. It technically is even more polished but the level design is worse and a handful of the boss fights suck. They focused on making the weapons just fun to use instead of making them all practical and I think it worked out wonderfully. Also has an endless mode that you could argue is better than 9's.
2008
In my opinion, the best classic series game. The only problem is that the game design will deliberately to things to kill you when you don't know they're there rather than giving you any chance to react or deal with it, but even then I understand that because this was a "return to form" and most people think of Mega Man as the kind of game that did that. Level design is otherwise fantastic, the enemies are really fun, the boss fights are the best in the series, the music is great, and this is the best set of weapons the series has ever given us. The endless mode existing is just icing on the cake.
1998
Brutally difficult and not in a way that feels fair. There's a masochistic side of me that enjoys it for that though, and the weapons are all really cool. If you play the game with Bass please do yourself a favor and let yourself play with the bosses' weaknesses because it takes a full minute to beat them at minimum otherwise.