Yeeee there was no drawback to just slamming all keys at once, except the slight cooldown before you can press it again, but its still mostly irrelevant.
In my earlier plans for the game I was actually thinking of making it a psuedo typing simulator (the name Dullahan Under the Keyboard began as a reference to keyboards and typing, until it fully embraced the keyboard as a musical instrument interpretation). Never enough time to spend on adapting/optimizing the gameplay - I locked it in too early and spent all my time on other refinements. Classic game jam things xD
Thanks for playing! :D