I see a lot of well-deserved praise here, so I'm going to try and offer some constructive criticisms that I'm not seeing brought up. The fact that you can use the artifact no matter where you are was not clear to me and may have cut off a ton of players just because of that miscommunication. When you read the sign, it implied to me that you press tab to use the artifact (which must be the sign) and then go from there.
I got lost several times because there is no indicator where you are on the map, but also because there's only so much you can do to make a tile look unique in monochrome style. I'd love to see a pointer for where I am even if it just tells me which tile I am on.
Early game you have to use your tile to explore the borders of the map which could be fine, but I thought it was unintuitive and more annoying than cool. The map doesn't show what borders are explorable, so it felt like a guess and check to find out if I lined myself up for a useful border connection. This is only annoying because of how early game you must slide tiles despite there being so much free room, so to check everything you slide along the borders.
The QR code was cool, I just wish it were placed differently in the slider order or that there was a better indication of what tiles had a QR corner. I definitely noticed the corners before but that doesn't mean I remember which tile had a corner and because of that I spent a lot of time slowly walking around the tiles to search for corners. I think the big thing here is just that you do walk kinda slow and you have a ton of ground to cover at this point.
When the river guy shows up, you aren't able to initially complete his puzzle (or at least that was my order). I got stuck here trying to figure out how to connect the two points I know exist but seem to be impossible to reach. I wish there was something to indicate you connected the right tiles to the borders, so then maybe you could connect both borders and say, "Well I know these are right, I'm just missing a piece" and get to the conclusion that I needed to reach which is that it's impossible for now.
I hate to admit this, but I accidentally completed the final slider puzzle and am genuinely confused about why that solution was the one. I do understand that you were supposed to line up walls to create a border, and the river pieces to help guide you to that conclusion, but the piece of the map that forms a U wall did not seem to belong anywhere and still looked out of place on the final solution. I can appreciate the difficulty of this, it is a proper slider puzzle after all. My point is that I wasn't actually sure what was the correct formation and might have given up if I didn't stumble into the answer. Visual feedback on when you place a correct tile could do wonders for establishing the intended final map.
Now if I had to speedrun my nitpicks...text goes a bit slow, water tiles do not look like water tiles when not connected properly (collision is wonky too), I found several spots where collision does not match the graphics (thankfully nothing game-breaking), the tangled orbs felt really out of place and like busywork because of a slow walk, I wish you had a more open connection tile closer to the start of the game to make exploring a little smoother, and I wish the water/river parts on the tiles looked more different from the walls (similar colors, sorry I'm a lil colorblind).
Wow I wrote quite a lot, but I also played quite a lot here. You have a chunky experience of a game jam game here and I absolutely loved it. It amazes me you got all of this done and balanced progression in just 48 hours. If I don't see this in Mark's top 100 somebody obviously isn't doing their job here haha. Cute aesthetic, great job on guiding the player, most tasks feel intuitive enough to want to continue playing, and the music managed to not annoy me after spending maybe 15+ minutes playing this. Phenomenal work here and I hope you consider publishing this in some capacity!