It's a really cool concept i just think the difficulty is way to much to start. The speed you start at feels like the speed you should be at after like 5 minutes of playing. I think you could improve the gameplay by making the beginning a lot easier and ramping up the difficulty in a smooth way that makes it feel fair to the player. This could also help your game be playable by a larger audience, bc as of now the only way to make it somewhat far in the game is to have extremely good reaction time and sense of where the numbers are on the keyboard. But again, I thought the idea was still pretty cool and enjoyable, and with a better difficulty curve I know this game can be even greater :) Good job!