Pretty good boss all in all. Weird and at times unintuitive, and perhaps it's just a bit too hard for its own good, but the more I play this boss the more I like it.
Some notes: in phase 1, you can just run up to where phase 2 starts at any time to 'skip' it, but any damage you didn't deal will have to be dealt there (phase 3 doesn't start until half HP no matter what). Healspots a pretty sparse here, but you can slip some in if you dodge laser early. If striking from below, aim for the tip of its butt, as it can and will swipe you with the legs if you're any closer up than that.
Phase 2 has an attack where shotgun blasts of 5 lasers pelt you up to 5 times. Of all the attacks the boss has, this one feels possibly the most luckbased, it didn't happen in this fight but sometimes it feels like it'll get you no matter what you do. There's 2 variants of bullet hell, sweeping and a 'wild' one. The sweeping bullet hell has a big blindspot at the side to heal in (don't go too far, leaving the cone entirely ends the attack early and has it blow a quick laser at you) and the wild one seems to aim most of its bullets roughly at you, so it seems best to keep moving during it rather than hunkering down and dodging in one spot.
Phase 3 introduces 2 main new moves, the first is the rapid and then sweeping spread laser. This one took the longest to figure out, but doing what I do works most of the time. You can heal or get a punish after it. The other is 3 variations of going grounded. The explosive one is the other move I feel is most BS, sometimes you're just going to get blown up. While grounded, it likes to jump 5 times, sometimes less if its positioning is awkward. It feels like jump 1, 3, and 5 are aimed at you but I'm not 100% sure. Again, can heal as it lifts back off into the air.