Hey Sparky, thanks for the kind comment :) I'm always happy to receive feedback, so thank you!
You're right - I had the same issue with the shift-key. I will add the right mouse button and Ctrl as alternative sprint key.
I had nearly no time to playtest the game's difficulty on my own, and one of my playthroughs gave me the same impression. Unfortunately, it was already too late to change the order of the levels. I will add new levels and tweak the current ones.
The hit detection is a bit weird in general, even with the normal-sized numbers. I already added a simple crosshair that indicates when a number is in range.
The Update will follow next weekend! The game will receive only one after jam update, because I want to get back to my main project!
Thanks again for the feedback! I'm really glad you liked the game. :)