Kaze!! It turned out so lovely!! Sona is so cute and cool and I did not guess what they would do at all but in retrospect it's kind of obvious.

Long comment with all the spoilers beware.

Anything I would complain about is either a "this was a 3 week project" thing, or you already mentioned it on the bugfix bucket list in the artbook, so I'll refrain from those.

I've only gotten 3/5 endings and I think I'll leave it at that for now! I'll probably come back later for it though. I think the overall message actually causes that -- the game says that all experiences are worthwhile. As were the player's, so. You really hit that dreary yet hopeful atmosphere super well.

The events were neat the first time you saw them but it's super easy to figure out how to "win" them. It can feel kinda unfair that not all of them have a choice element, so sometimes you're just gonna lose Spark whether you like it or not. It's also a bit weird that Distance doesn't seem to do anything (though I see you have plans to make it a requirement for the Infinity ending). I thought that maybe the heat death of the universe could catch up, and that'd be one of the endings, but then i got -1000 distance by trading Sona some time and nothing happened. We stay Sparkmaxxing.

Speaking of Sona, though! I really liked them! Their music is great (though it often doesn't play long enough to really pick up), and they always brought a welcome reprieve to the events. And their gifts made it easier to keep up with Spark, too - a good counterbalance to how RNG can screw you over, lmao. Their design is fun, their poses are dynamic, and they have interesting things to say! On a replay, I can definitely see how they're kind of callous with the protagonist at first. Their bad deals add a lot to the personality. In the artbook, you say it's because they don't really care (at least in the beginning), but to me it also reads that they like... forgot? How squishy humans are? Because their bad deals seem to come from not thinking things through. Like giving the protagonist a highly irridated object.

Also some good foreshadowing in how wistful they get talking about escaping the heat death of the universe. There's a lot to be gleaned from what portraits they use! It's very cool.

Another cool detail is them greying out after saving the protag, which makes them look all the more like the other former people the protag has encountered so far. It's like a visual representation  of that lost trust, considering Sona was the only spot of color besides the void of space.

My first time getting this far (my first playthrough ended with running out of Spark on Event 1), Sona gave themself up to let the protag succeed, and it was a pretty effective scene. The "this seems like a great spot to talk to someone" scenes after damn well got me to tears. Almost. It's  a real gutpunch!! I really missed them!! I did get to infinity thanks to their sacrifice, though.

Very neat that the random events change after this. That the protag is also Something More, now, and can do to others what Sona nearly did to them. Weh.

All around, a very neat and atomspheric little experience! Fantastic for a first game! So you get the five stars eheh.