Alright, first of all I loved the different planets and mechanics each had: Brittle Hollow, Giant's Deep, Dark Bramble, etc. It was cool that each planet had it's own thing going on, and seeing them change in real time was neat. I probably spent the most amount of time in Brittle Hollow, I just enjoyed the black hole perspective and the aesthetics. Giant's Deep was cool too.
The space travel was fairly well done. It was simple, but it obeyed the rules of physics as far as gravity, objects staying in motion in an absence of gravity, trying to reverse course in space after moving in a particular direction requires time to course correct, etc. I did overshoot some targets a number of times when not using Auto Pilot, which can be expected.
Some quick hitters now. The instruments and how they tied together was neat. It was cool that you could reach across space and always know where your old buddies were in the grand scheme of things. I liked the art style, simple but it worked. I liked the puzzles and the "dungeons" as you made your ways to POIs. The rumor board was a nice way to track what you've found and what you're missing. The story was mostly written via messages left by the aliens that you have to search for, reminded me a bit of Dark Souls in that respect although it was better put together from a narrative perspective. I can see why greyhammer enjoyed this game in that respect.
Now, the things I didn't care for. I'm going to come out and say it: I generally love time travel as a plot device, but I HATE time loops. Absolutely hate them. Time loops can bring about some interesting features, but depending on how they're done they can also be a strong source of frustration. As an example: I'm trying to get into the Tower of Quantum Knowledge on Brittle Hollow. It's impossible to get to the top until the Tower gets sucked into the Black Hole, which happens roughly 15-16 minutes after you wake up from a new time loop. Until that 15-16 minute mark all you can do is plant your Probe inside and then you're just sitting around doing nothing. Sure, you could go off and do something else (Unless you've already done everything up to this point), but you also risk missing the event and possibly having to start over. Once the tower gets sucked in you have to jump in your ship and quickly chase your probe to the new location of the Tower as it floats in space in zero gravity, allowing you to finally get to the top of the Tower. You get to the top of the Tower, read a message, and then on your way back down you see another Scroll you need to read. You grab the scroll, head back up to the next floor to read it, and then you hear it...sun implosion imminent. Sure enough, you get engulfed in blue light, wake back up at the fire, and you're heading back to Brittle Hollow to sit and pick your nose for another 15 minutes and hope you can beat the clock this time to view the Scroll you missed.
That's the big downside to time loops with scheduled events. If you miss a tiny window it can end up costing you a lot of unnecessary time as you wait for the window to return. There's a number of those windows that you're forced to wait through. I can't tell you how many times I waited by the 2nd tower on Twin Ash for almost 10 minutes, waiting for the sand to clear so I could teleport for the warp core...only to get eaten by the Anglerfish in Dark Bramble and having to start over. Anytime I'm just standing around in a video game, unable to do something, I begin asking myself "What the hell am I doing?" Waiting 10-15 minutes for anything to happen in a game shouldn't be happening. Give me the option to snooze or something till the event occurs, whatever. Anything, as long as I'm not just sitting there in space and questioning my existence. For that reason, time loops are awful as a plot device. Not only do they rely on repetition to fill game time, but the "event windows" I mentioned also create unnecessary time sinks that waste gaming time unless you manage to pull them off perfectly the first time (Doubtful given the mechanic is built on learning and remembering pitfalls to avoid during the next loop).
Time loop aside, I thought the game had a fair difficulty level for the most part, not too easy not too hard. The Rumor Board on the ship was helpful to find where to go next and if anything got missed at a particular POI. I did find myself having to go back to a few locations multiple times because I may have missed something, like a message in the Southern Observatory on Brittle Hollow, or a Scroll in the Sunken City. There were a few puzzles I got a bit stuck on and had to look for advice online. For instance, in trying to get to the Twin Ash Project I kept getting sucked up into the Sand Tornado when trying to use the teleporter. Apparently it's very touchy, you have to basically make a run for it (Avoiding the cactus) when in the eye of the storm. I probably missed it 3-4 times, had to restart the time loop, then found out I was going too early apparently. I had a hell of a time with the 3 Anglerfish in Dark Bramble. Tried my best to avoid even the smallest of boosting so I could coast by them, but they always seemed to find me somehow. It wasn't till I saw a suggestion to get out of the ship and use the jetpack that I made it through finally. I thought the other sections of Dark Bramble weren't bad with the Anglerfish, but that section right before the Vessel with 3 fish just waiting at the entrance? That was a bit excessive, at least for a game built on 22 minute time loops that force you to hurry. It wouldn't be so bad if I didn't need to spend another 15 minutes getting back to that point so I could make another attempt. Speaking of Anglerfish, I didn't find them particularly scary...but those Quantum Rocks always teleporting around you? Creepy as fuck.
Overall I was really enjoying the game up until the end. I had to spend way too much time just waiting around for that Tower to get sucked into the Black Hole twice, and then waiting for the Tower on Twin Ash to get uncovered so I could make another attempt at bringing the warp core to the Vessel, and a number of other event restricted gateways that force you to just sit around doing nothing. It's one thing if you're playing a video game, you fail a boss fight, and you end up having to restart the fight. Typically there's a save just outside the boss' room, so you jump right back into the action. If I had to sit around and do nothing for 15 minutes and wait for the boss to show up? Nope, you're needlessly just wasting my time then. I ended up getting the traditional ending with the instruments and the forest. The ending itself left a bit to be desired I thought. I read there are some paradox endings as well, but they're not really the "good" endings so I don't think I'm going to pursue them.
Given the similarity to Majora's Mask I can see why you liked it
@greyhammer90. I didn't care all that much for Majora's Mask for the same reason: time loop bullshit, although I don't recall there being a bunch of events in Majora's Mask that force you to wait around and I'm pretty sure you could advance time in that game. I think Outer Wilds is a good game, but I think the Overwhelming Positive reviews it's gotten are a bit overhyped.