I had to watch it for myself. I went in blind, knowing there was some controversy and also that it was "anime of the season".
So, best I can tell:
Underbudget studio of 10 people are commissioned to do a shitty mobile game tie-in anime. The director takes it on as a passion project and pours every ounce of heart into it. Bad acting, bad animating, but hella fun.
And it was. There's actually an interesting storyline that unfolds beneath each episode's fluffy surface.
Anyway. It's a good anime. Nothing groundbreaking like Evangelion. Just unexpectedly nice. Kind of like how Nichijou was surprisingly hilarious, this was a pleasant soul-cleanser. Cute and innocent, and in some respects very dark.