In the sparring tutorial in the first five minutes of the game, if you get hit and knocked to the ground, the pop-up demanding that you drink a potion freezes the game, not allowing you to proceed until you do so.
Except you can't drink your potion with the game paused, and the game will not allow you to unpause until you do. (you close the prompt and the game progresses by about one frame, before it freezes the game again to show you the potion-prompt.)

This is both extremely frustrating, and a progress-blocking bug.
As far as I can tell, the only solution is to just close the game down.
I reported this for the first time back in November, in a thread that was never replied to.
Please fix this promptly.

Just erasing that tutorial prompt entirely would be preferable.