This project is so bad, anyone with basic physics and electronics understanding can tell it's bad. Unlike @sleepybrett I never even built a keyboard in my life and yet can I still find numerous problems with that keyboard. And I didn't even get to the MCU firmware part. I can only imagine how bad that is.
If this project was done only to learn, then why is it here? People don't usually brag about what they learn. (Look ma! I put 3 lego bricks together.) I mean, it's perfectly OK to build projects to learn, make mistakes and learn from those too - I wish I had time to do that myself - but showing it on HN as if it's some viable product? Don't do that.
Why are you defending it? Just because it looks "cool"?