Really love the idea of using just one hand to play. It's super clever and makes it challenging in unique way.
I saw in the GDD that the aiming was added on purpose to increase the challenge, which makes sense. Still, just as a thought, having an option where it auto-attacks the nearest enemy could be interesting for a more casual/accessible mode, and keep it more in theme with using only one hand.
A left or right handed option could also be a nice touch for accessibility.
If you decided to lean into an educational angle, this idead could make a fun game for helping people improve their typing speed.
I find the level a bit dark, so I cannot actually see the details of incoming enemies.
Overall, this is an awesome idea and genuinely fun to play. Great work!