Ultros does that thing where the game that you think it is when you start playing is but a sliver of the game it becomes by the end, and as such I want to avoid any major spoilers for the mechanics, which is a problem because this game is all mechanics. The story is, if we're being generous, fairly opaque. If we're being less generous it's nonsense, just a bunch of tropy sci-fi/weird horror stuff tossed in a pot and stirred together until it turns rainbow. It's the gameplay that keeps this mess from falling apart and. It's. So. Goddamn. Good. And so much effort is put into making each phase of the game feel like a full game. Like, there are incredibly clever design decisions that only really matter for the middle 10 hours of the game.
I say phases but just to be clear, this isn't like Inscryption or Nier: Automata—Ok, well it's more like Nier: Automata than Inscryption—but anyway the point is there aren't exactly distinct phases of the game in that way. You play as the same character the whole time, on the same map. But as you collect abilities what you're able to do changes so much that what you're trying to do will also change, and it's these developments that naturally give the game a sort of 3-act structure (or like, 2.5-act? The 2nd and 3rd acts can overlap a bit depending on how you play.)
The game also does very little to explain itself explicitly, with only cursory tutorials of the core mechanics and the various plant types. But there's plenty of diegetic guidance, whether it be blocking off all but the key route at certain parts of the game, or placing an item right next to a good spot to use it so you can immediately start to learn what it does. On the early occasions when I started to feel stuck and frustrated, I just kept playing, exploring every possible avenue, and eventually I figured what the game wanted me to do next by dint of it being the only possible thing to do. And after each such occasion I immediately discovered a new ability or item that opened the map up in ways it hadn't been before, which is the absolute peak experience of a metroidvania. Do yourself a favor and avoid walkthroughs for this one for as long as you can (I did look up a plant guide later in the game when I was starting to get into the nitty gritty of the horticultural mechanics, but that was well after I got the first of the three (as far as I know) possible endings.)
That being said, toward the very tail-end of my experience, when I was trying to do a few very specific things to get to the last few unexplored spots on my map, I did start to get frustrated, not just with the game's lack of explanation, but also with the jank that was becoming more and more apparent, and the tedium of having to restart the loop over and over just to progress one particular goal. What really got me was putting probably upwards of 5 hours into accomplishing a specific task (that I don't want to spoil the nature of) to get a part of the map, before finding, in quick succession, 1) a better way of doing it that I could've been doing all along, and then 2) a workaround that skipped this task entirely that I could've done at any point and that would've saved all 5+ of those hours. After that I found my enthusiasm waning and I figured I should wrap it up before I really started to hate this game.
So, while you can get lost in the weeds towards the end, for the most part Ultros delivers the best of what a metroidvania can be, gameplay-wise, and does so with smart, thoughtful design, and with innovative mechanics that you'd be hard-pressed to find anywhere else.
p.s. Also, I played with the sound on the whole time and never once put on a podcast, which is rare for me for games that are neither story-focused nor particularly reliant on sound cues. The music is decent enough but mostly it's just that the game has a vibe and I never felt bored enough to mess with that vibe.
p.p.s. As much as I poo-poo the story I did like the reveal that the bottom area of the ship is a luxury resort that was founded by people who I guess just discovered the ship floating in space and they're just like, "Were ancient gods worshipped here? I dunno, probably. Enjoy your complimentary mai tai!" It's pretty funny, but also the idea that this whole ship is just layers of civilizations increasingly removed from its origins is neat.