Ah yes, the classic draw a boy and call it a girl switcheroo
Letting misunderstandings about identities brew without any attempt at proper communication is really just a pet peeve of mine. It does have Kanchigai Sareru in the title, so I know the "getting misunderstood" part is central to the plot... But still, I was hoping either she'd tell him or he'd realize at the end, but no such thing happened after all. Doesn't help that I prefer long hair on girls, and her trading her pretty long hair off for a most boyish pixie cut was disappointing to me.
I wouldn't call this bad per se, but I guess it's just not my cup of tea in the end.