I had a lot of fun with X4, but it's one of those games with really high highs and annoying lows for me.
I first started X4 way back when the legacy collection first came out in 2018. At that point, I had just binged through X1-X3 back to back and I started to feel burned out (this feeling was especially strong after I finally managed to finish X3's final boss). I ended up taking a break about 1/3 of the way through my X4 playthrough and didn't pick it back up until this year.
Presentation wise, X4 looks great. It took me a bit to get used to the new art style since I really love the sprites from the SNES games, but it really grew on me and feels like a nice step forward visually. The animated cutscenes look really nice too and could be surprisingly brutal at times (there's more some of the X4 cutscenes than some M rated games I've played). The english dub voice acting is also really funny to the point where it kind of comes around full circle and adds to the charm of the game (it's definitely nowhere near as bad as the Megman 8 dub for comparison).
In terms of the usual megaman x action and gameplay X4 is probably the best feeling and most polished so far. Runnning and gunning as X just feels really good and the maverick stages are super fun. The X4 armor is also one of if not the best fully upgraded armor sets in the series so far. I especially love the helmet and buster upgrades with the buster upgrade that leaves behind the energy ball being my favorite upgrade of the set. I'm not the biggest fan of the new boots upgrade, specifically the hover ability. Being able to air dash horizontally is as great as always, but I preferred the upward dash from X3 and found the hover to be a little too slow and pace breaking. I also thought it was a little too easy to activate the hover accidentally while trying to wall jump during some of the more intense boss fights which could be a little annoying. It's not bad, but it feels more like a downgrade compared to X's air movement in the previous game.
Like the previous X games, there is some required backtracking if you're going for 100%. This can be kind of annoying, but it's nowhere near as bad as X3's and I think figuring out the best route adds to the games replayability. I ended up doing the 100% speedrun routes for both X and Zero since it reduces backtracking (you only return to 1 stage as X and there's no backtracking for Zero) and I thought it was pretty fun and provided a nice challenge (especially on the X playthrough since I rarely had any of the maverick's weaknesses).
The stage designs for the mavericks are mostly great as well. It's really amazing that the devs were able to build stages that fit two completely different gameplay styles perfectly.
The OST is a big step up from X3's, but I think it's weaker than X2's and X1's. The closest comparison I can think of would be that X4's OST is similar to Banjo Tooie's while X1's (and to a lesser extent X2's) OST's are similar to Kazooie's. Both are great and fit their respective games perfectly, but one is more memorable and catchy while the other feels more environmental and ambiance like. I just finished the game a couple hours ago and I can only remember one stage theme off the top of my head (magma dragoon's), but I remember liking the music while I played the game if that makes sense.
I found the bosses to be pretty hit or miss. I love pretty much all the maverick fights and the buster upgrade made them all super fun and engaging to try and take down without their weaknesses when playing as X. However, there are a few that felt kind of unengaging and tedious. Fighting the colonel as X is particular was probably the biggest low point for me since he's not particularly hard, but he's a bit of a damage sponge. This combined with his smaller hit box, his ability to block your attacks and his small window where he can actually be hit made for a boss that just kind of dragged on for too long (and you have to fight him twice as X).
I'm also not sure if this is a hot take, but I really didn't care for the final stage and sigma fight in this game. I think the decision to put the maverick rematch gauntlet and the final boss in the same level was a really bad decision. In the previous X games, you could leave the stage and grind out your sub tanks or just grind in the hallway leading up to the final boss if you died. You can't do that in X4 so if you use your sub tanks on the sigma fight, you have to either suck it up and fight him without them or quit the stage, grind and then go through the entire boss gauntlet again before you can get a chance to fight sigma again (which I learned the hard way). Please save yourself the time and if you're struggling with the sigma fight, don't use any sub tanks and take a few lives to learn his attack patterns. You only really wanna use those sub tanks if you get a good run and need a little extra health boost during the last phase of the fight.
Being able to play as Zero is also amazing and by far my favorite feature of the game. Zero's gameplay feels like another step forward in the MMX formula and provides another style of fast action packed gameplay that the series is known for. It feels really good blasting through stages slashing through enemies. I also really love how Zero's upgrades work and this upgrade system hit the same spot that finding an upgrade in a really good metroidvania makes you feel.
The bosses are even better with Zero's gameplay and I think the different gameplay style helped improve some of the weaker bosses from X's campaign. The colonel fight in particular was so much faster when playing as Zero and just felt so much better.
Unfortunately, I think Zero's campaign staggers a bit at the end similar to X's with the final stage once again being the low point for me. I really hope the maverick rematches and the final boss are separate stages in future X games since it ended up dragging here again in Zero's campaign for me. A few of the rematches ended up giving me more crap than I was expecting (especially since I knew I had to save my sub tanks for the sigma fight afterwards). Weirdly enough I thought the sigma fight was easier as Zero than it was for X though. I was able to deal a higher amount of damage more consistently with Zero's upgrades (especially on the head in the third phase) than I could with X and I was able to finish the fight on my first try without the sub tanks.
Overall, I had a lot of fun with X4, but the stuff that annoyed me really annoyed me. I think part of that might be the game being overhyped for me. I don't think it's the best of the X series and X1 is still my favorite, but it might be the second best (I would need to replay X2 before I could decide for sure). I could see my rating going up with future replays. I'm already excited for my next inevitable Zero playthrough.
I first started X4 way back when the legacy collection first came out in 2018. At that point, I had just binged through X1-X3 back to back and I started to feel burned out (this feeling was especially strong after I finally managed to finish X3's final boss). I ended up taking a break about 1/3 of the way through my X4 playthrough and didn't pick it back up until this year.
Presentation wise, X4 looks great. It took me a bit to get used to the new art style since I really love the sprites from the SNES games, but it really grew on me and feels like a nice step forward visually. The animated cutscenes look really nice too and could be surprisingly brutal at times (there's more some of the X4 cutscenes than some M rated games I've played). The english dub voice acting is also really funny to the point where it kind of comes around full circle and adds to the charm of the game (it's definitely nowhere near as bad as the Megman 8 dub for comparison).
In terms of the usual megaman x action and gameplay X4 is probably the best feeling and most polished so far. Runnning and gunning as X just feels really good and the maverick stages are super fun. The X4 armor is also one of if not the best fully upgraded armor sets in the series so far. I especially love the helmet and buster upgrades with the buster upgrade that leaves behind the energy ball being my favorite upgrade of the set. I'm not the biggest fan of the new boots upgrade, specifically the hover ability. Being able to air dash horizontally is as great as always, but I preferred the upward dash from X3 and found the hover to be a little too slow and pace breaking. I also thought it was a little too easy to activate the hover accidentally while trying to wall jump during some of the more intense boss fights which could be a little annoying. It's not bad, but it feels more like a downgrade compared to X's air movement in the previous game.
Like the previous X games, there is some required backtracking if you're going for 100%. This can be kind of annoying, but it's nowhere near as bad as X3's and I think figuring out the best route adds to the games replayability. I ended up doing the 100% speedrun routes for both X and Zero since it reduces backtracking (you only return to 1 stage as X and there's no backtracking for Zero) and I thought it was pretty fun and provided a nice challenge (especially on the X playthrough since I rarely had any of the maverick's weaknesses).
The stage designs for the mavericks are mostly great as well. It's really amazing that the devs were able to build stages that fit two completely different gameplay styles perfectly.
The OST is a big step up from X3's, but I think it's weaker than X2's and X1's. The closest comparison I can think of would be that X4's OST is similar to Banjo Tooie's while X1's (and to a lesser extent X2's) OST's are similar to Kazooie's. Both are great and fit their respective games perfectly, but one is more memorable and catchy while the other feels more environmental and ambiance like. I just finished the game a couple hours ago and I can only remember one stage theme off the top of my head (magma dragoon's), but I remember liking the music while I played the game if that makes sense.
I found the bosses to be pretty hit or miss. I love pretty much all the maverick fights and the buster upgrade made them all super fun and engaging to try and take down without their weaknesses when playing as X. However, there are a few that felt kind of unengaging and tedious. Fighting the colonel as X is particular was probably the biggest low point for me since he's not particularly hard, but he's a bit of a damage sponge. This combined with his smaller hit box, his ability to block your attacks and his small window where he can actually be hit made for a boss that just kind of dragged on for too long (and you have to fight him twice as X).
I'm also not sure if this is a hot take, but I really didn't care for the final stage and sigma fight in this game. I think the decision to put the maverick rematch gauntlet and the final boss in the same level was a really bad decision. In the previous X games, you could leave the stage and grind out your sub tanks or just grind in the hallway leading up to the final boss if you died. You can't do that in X4 so if you use your sub tanks on the sigma fight, you have to either suck it up and fight him without them or quit the stage, grind and then go through the entire boss gauntlet again before you can get a chance to fight sigma again (which I learned the hard way). Please save yourself the time and if you're struggling with the sigma fight, don't use any sub tanks and take a few lives to learn his attack patterns. You only really wanna use those sub tanks if you get a good run and need a little extra health boost during the last phase of the fight.
Being able to play as Zero is also amazing and by far my favorite feature of the game. Zero's gameplay feels like another step forward in the MMX formula and provides another style of fast action packed gameplay that the series is known for. It feels really good blasting through stages slashing through enemies. I also really love how Zero's upgrades work and this upgrade system hit the same spot that finding an upgrade in a really good metroidvania makes you feel.
The bosses are even better with Zero's gameplay and I think the different gameplay style helped improve some of the weaker bosses from X's campaign. The colonel fight in particular was so much faster when playing as Zero and just felt so much better.
Unfortunately, I think Zero's campaign staggers a bit at the end similar to X's with the final stage once again being the low point for me. I really hope the maverick rematches and the final boss are separate stages in future X games since it ended up dragging here again in Zero's campaign for me. A few of the rematches ended up giving me more crap than I was expecting (especially since I knew I had to save my sub tanks for the sigma fight afterwards). Weirdly enough I thought the sigma fight was easier as Zero than it was for X though. I was able to deal a higher amount of damage more consistently with Zero's upgrades (especially on the head in the third phase) than I could with X and I was able to finish the fight on my first try without the sub tanks.
Overall, I had a lot of fun with X4, but the stuff that annoyed me really annoyed me. I think part of that might be the game being overhyped for me. I don't think it's the best of the X series and X1 is still my favorite, but it might be the second best (I would need to replay X2 before I could decide for sure). I could see my rating going up with future replays. I'm already excited for my next inevitable Zero playthrough.