I dont think the accuracy is working as intended, it doesnt really seem able to reach 100% and there doesnt seem to be any 90+ or something, it will just tick with bad regardless of how visually full it looks like, may be a resolution problem not allowing for this
I tested the game at various resolutions, and the results were roughly the same. I probably just made it too difficult. To get a "Great" rating, you need to keep the cursor on the target point (the circle on the right) while maintaining the required speed (indicated on the left). It’s also possible there’s a bug related to the browser or mouse sensitivity.