Thanks for the nice feedback!
The element, which decides on the direction you shoot in, was actually the most difficult to design for me. The current solution is quite deterministic, which I like: The net movement of the 5 note pattern decides on direction. The disadvantage is, that you always have to approach the monsters you want to fight, which creates the need for enough space and attacking monsters from a distance early. I thought about a button to mirror the direction wheel, which lets you shoot in the opposite direction...
This might be part of (potential) future updates, as I left a lot of things out, like powerups (which give you more flexibility, or heal you) or monster spells (which restrict you, e.g. on the direction wheel). I am sure I did not fully explore the design space here. E.g. the inner white square of the direction wheel is a leftover of a "3-note-mode" which I eventually did not pursue further.
Regarding sound: This would be really nice! As libtcod does not support sound itself, it was out of scope for 7drl. I have no experience with sound libraries/modules in python yet, in especially how to include it to the particular code. Are there some examples of libtcod games in python with sound? I would be happy, if I could include it at some time.