I think your idea is more akin to a traditional rhythm game. (compared to mine)
My game is more like "Beat Saber" where you don't actually have to be on rhythm in a way and the accuracy is based on other things. In Beat Saber the accuracy is based on how precisely in the middle of each block you strike.
Some call this "passive" type of rhythm game a "music game" instead actually.
It took me some time but I found the game yours reminded me of. Check out "Project Rhombus" on steam.
I actually remembered it from an Osu! Lazer custom game mode "Hishigata" https://github.com/LumpBloom7/hishigata
I just now checked out what it's based on. It's actually also more of a "music game" than a proper rhythm game.
Anyway some feedback for your actual game:
The triangles should be more pointy or have some other way of distinguishing between different directions easier.
Of course you had the color (and flashed the whole screen for said color) But I actually only noticed the flashing while writing this comment and not during gameplay.
I saw you said in other comments the notes were random since you didn't have time to implement it properly.
You have to use the playback position of an audio file to have a proper metronomic rhythm game where the notes don't drift out of sync with the music.
It was my first time doing it as well but if you need some resources or help you can shoot me a dm! 😁