Hell, those who supported early access and initial release on Steam, included me, basically feels being cheated (the OST DLC even has music for the very fight! WTF)
Cirno isn't even a character being related to Microsoft mascots by anything so there's no goddamn reason for such a fight being Microsoft exclusive at the first place
What's worse, Steam page didn't get any notice and stuff about such event (or should be called "incident" for accurancy's sake) by now
Honestly if something similar happened again and again in other Steam indie 2D action games I'd be sure lost all hope for the future of such genre