tl:dr - This game is great if you like coding and puzzles. This game is good if you do not. Runs well on Windows 7, despite the minimum requirements being Windows 8.1.
A fun change of pace from normal visual novels. The character art is a bit of an acquired taste but by no means completely ruined the experience. The story is...meh. It's not bad, and I've definitely played worse. I just expected it to last longer. Maybe I didn't get the "true" ending (there's no way to know without looking through the Community Hub, since unless I'm mistaken there's no achievements), but I did get an ending that felt mostly satisfactory.
I do want to mention the puzzles. The puzzles are and should be the main draw of this game, as they are the biggest change from normal VN style. As someone who can't code above basic HTML text formatting and got a C in the last algebra class they took, the puzzles sucked from a difficulty standpoint. I don't think this is inherently negative, though part of me wishes there was an easier mode. The puzzles take up the most time in gameplay, and if you're like me and none of the instructions made sense, they'll take even longer. I think having a less...code-y explanation for how the puzzles worked might have helped me. For example, instead of using the equation given for the Match puzzles, I used the hint that said what a "1" in each category meant (8, 4, 2, and 1) and then added the numbers given in each code. (i.e. 0101 is 5. I think.) I also highly recommend, for that specific type of puzzle, taking a screenshot of the grid and writing the numbers on top as you go.
I also wish the hints were a bit more helpful, or that you could access your journal while in a puzzle. There's a whole section of the journal that acts as a guide for the puzzles, and I can't see it when I need to look at it most. By the time you get to the last level of puzzles it's hard to remember which shape is a XOR or a NAND, and having a cheat-sheet there would be a big help.
I haven't spoken about the story much because it didn't leave much of an impact on me. I wish we'd gotten to speak to each side character more than once. I wish we'd gotten more time to interact with Grace's mother. Aside from Ivan, most of the characters feel decently human, but since we only get one scene each for them to deal with each other, I don't feel like they got much of a chance to fully develop. As much as the ending that I got tries to say that Grace became a nicer person and Ava became more human, in my opinion they were like that from the start because of the way I played them. Why would you be mean to Ava? She's your help. She's the character you're clearly supposed to be nice to to get the good ending. The only reasons I would choose other options would be to get achievements from the other endings. Once you take the puzzles out of the game, the remaining story isn't much to sniff at. And the "twist" of the only character you don't get to talk to in the game (aside from the dead one) being the one who killed the dead one felt like a joke. Again, maybe that's just the ending I got, but to be honest, it sucked.
At the end of the day, despite my complaints, I still recommend this game, particularly to anyone who likes or is good at math or coding. It's short enough to be worth the time, and the concepts explored through the puzzles are interesting enough to play through at least once.
One last thing - I didn't notice until after I'd played the game that the "minimum requirements" are for Windows 8.1. I played this game on Windows 7 32bit, and it ran like a charm. So if you're in my position software-wise and are debating whether or not this game will work, it likely will.
