I usually don't like commenting in games lashing out but this is outrageously bad. The horror aspect to the game is simply not there. The game is not scary whatsoever, just slightly unsettling in the beggining. Some cuts inbetween rounds with soft storytelling about the stranger would have made you actually feel more insecure about everything and maybe actually scared.
Also, the gameplay is just unbearable. Many collisions are really junky and feel unfair, specially the speed at which the stranger moves by the end. The mouse is also uncontrollable because you don't even know if you're in range of hitting the ball or not, that's even assuming you manage to put the cursor over it given you can only play at one horridly rapid mouse sensitivity. A sensitivity slider and some vidual clue that you can hit the ball (like the cursor becoming slightly bigger, for example), would make the game 1000 times better.
And before any of you call it a skill issue, here's me beating all 4 rounds: