A pretty good follow up to X. Still wouldn't say it quite gets to the original X's standards. There are some things it does a bit better but with that also some things it does worse.
For one, that Sigma stage 1 is a war crime. In general, the Sigma stages give X's a run for its money which while having some dumb enemy placements didn't toss insta death around all willy-nilly. Though actually having to use some the sub weapons for exploration there was admittedly a nice touch and in truth I didn't really struggle on any of the stages save that 1st one. I would say the main stages are on par or just under X1's levels.
Bosses are a bit of a mixed bag, the good, the bad, the ugly of sorts. The X Hunters felt like one was a 1 dimensional meme with no real sauce, the other extremely exploitable (but decent fun) and last one was just a big jerk that lived up to the threat he made on crushing X by doing so much more damage than the other two and having unga bunga with mix ups. In the rematches it turns around a bit like the meme becomes the difficult one, the scarier one will actually become fairly exploitable (if you keep him low but if you let him go high though he'll do his best impression of Obi-wan striking down Anakin from the high ground) and well the exploitable one becomes a meme I guess (double points if you get shouken from his stage and you end his life in like 20 frames of boss battle start).
As for the Mavericks they range from exploitable easy, normal easy, to if I don't do specific thing im gonna suffer or why did that do so much damage (Morph Moth contact damage comes to mind). Some have pretty cheesy gimmicks that if you don't have their weaknesses or the know how you're just gonna have a bad time like Magna Centipede (namely this) or Snail's slow down. Some bosses will spam said cheesy stuff alot seemingly out of desperation like gator just fucking off into the oil lake after just doing that sometimes with barely a real damage opening which does kind of hurt the pacing abit but overall it's not the worst outside of Centi. Weaknesses actually tend to have less power against the bosses than Buster Charge shots especially after the arm upgrade that said still not in a awful spot. Buster shot being extremly powerful is still pretty nice especially coming off X's pretty underwhelming buster upgrade.
The Sigma fights difficulties are actually well distributed (and felt more fair as a whole) this time in my opinion which was nice coming off X where final Sigma did like 88% of the damage to me while phase 1 and 2 just kind of just existed for the sake of it.
That said having that mini section of Magna's stage before Sigma with no checkpoint is a bit of a dick move (and a bit lazy) but not a deal breaker especially with the high chance of health drops from the Block section. I loved the convenience of the water level giving you 1ups and with silk shot charge a ton of energy for your subtanks. That shit is pretty dope. Pretty good game overall.