Well definitely not the normal kind of shape game setup I'm used to seeing, got a nice little story here though which definitely adds a bit to the game and gives a  bit of incentive.  It is also nice that it fits with the gameplay to give buffs.  

Although it is a little weird that they gives buffs since everything is real so I guess Triangle has some sort of mind control power top create buffs or something and he used it based off what Circle said?  At least that's what I imagine from my perspective.

Gameplay wise though, dang is it hard.  I honestly only won because I managed to bug myself into a wall, by accident and then proceeded to murder everything from inside the wall.  It's definitely a  bit of a jumpscare when all of sudden there's squares LITERALLY everywhere.  I knew he said they were everywhere, but I didn't actually believe that part.  Although it does add a bit of flair to gameplay the way that they work as physics objects and just are intent on murdering you and nothing else.  Although pathfinding would help a bit.

It also seems like there might be a bit of.. sort of used strategy with blocking the squares with physics objects.  The doors etc.  which I managed to do by accident a bit, though obviously not consistently since there doesn't seem to be a way to block, could be wrong, maybe the player can stop the doors opening.  Although if so then the player is a little too slow compared to the squares.  They are the flash of Square armies I guess.

Overall though a really well done bullet hell base, with some iffy stuff on movement speed and dashing to randomly Go Ghost and phase into walls.  Plus that added spice of the visual novel element, which sort of helps gameplay obviously, it's not ever present but it is an interesting addition to the game overall.