It's an OK game, I'd give it a 6 out of 10 as in "decent enough and does what it claims to do". At the moment of writing I played less than an hour. I recommend it for people who simply like these kind of games and want a random session to waste some time with. I don't recommend it for people who want to experience some kind of progression and people who want the solutions to form a picture.
I played one normal 15x15 level, then cheesed the achievements with 2x2 grids. Got 16 of the 22 achievements in 30 minutes. The 15x15 grid didn't form a picture. As far as I can tell all game sessions are randomly generated, although I saw the dev comment somewhere that there are pictures.
Then I wanted to check out the massive 99x50 grid, needed for an achievement, but the resolution on my laptop screen was to low for it to fit in (M1 Mac Air). After changing the resolution, it took around a minute to load a game. At that large a scale, the game seemed to lag a little when placing points on the grid. It was playable but all the numbers were very small to read.
At such a large grid scale it would help if I could click on the numbers of a row or column to highlight it with. Highlighting can be enabled in the options but it only highlights where the cursor is pointing at.
Maybe a little screen showing the x,y coordinates where your cursor is pointing at would be helpful as well, so you don't need to count that much. Or at least some numbers at each fifth grid line.
I didn't see any possibility to save, which means I would need to sit through the mega grid in one session. Looking at the results of other people, it takes at least more than one and a half hours to complete the 99x50. Maybe I missed it somewhere but it seems like a crucial feature.
