Thanks for the feedback! I should add more cues to help the player get started quicker as you said, I dropped the ball there for sure. Something else that I found is that tempo is kind of hard to get right. I started by making the game go at a regular 120 bpm, however I found that by keeping it low, it's easier to teach the game, but at the same time you make the player have to spend more time for the same reward and the player must play safer and slower, making it more boring/tedious and having to plan from even further ahead, so I went with a 140 bpm which (I think) I once heard was about the upper limit on the speed that people normally talk at, but I do agree that it may be too fast to start off there, maybe have it ramp up alongside the challenge would have made for better balancing.
Also I have a small question about the hand position thing. How is your keyboard layed out, how big is it, about how tall are the keys and could you provide with maybe a drawing on your position? This part has me a bit intrigued because I never considered the ergonomics being too harsh here, I really just felt it like a small piano, but it probably is different on different keyboards and different hands. I absolutely should have designed around such cases because everyone is different and their keyboards are too.
The drum beat thing being displayed visually and such is a good suggestion. I got to be honest here, the only rhythm games I've watched (not even played) are Guitar Hero and Piano Tiles, in reality I just wanted to try something new, but in retrospect that was probably the biggest overlook ever haha. Thanks for making me remember the importance of looking what others have done before every once in a while to fix some issues I might not have seen.
Again, thanks for the very insightful suggestions. They will come in really handy if I ever want to make something like this game again or decide to make it a bigger thing. (I mean, some of them, specially when thinking about the moral of their story, will come in very handy for game design in general anyways, so thank you!)