GuitaRPG started development somewhere around mid-2012, when I (srylain) decided I wanted to make a game that I wanted to play. XNA was the first engine I used, and at the time the game looked more like DDR(Dance Dance Revolution) or Rock Revolution because of the top down perspective. It even had extremely basic online multiplayer because everything I was doing at the time I made have extremely basic online multiplayer (stuff like Pacman clones, Bomberman clones, Tetris clones).
Then came the first change.
After a while I tried doing a 3D perspective, all in 2D mind you, and it sucked. Hard. So I then quit the project and picked it up a couple years later after I had moved on to using Unity since XNA was killed by Microsoft. At that point I decided I didn't want to do an RPG anymore because of all the work involved, and thus the game became known as GuitarGame. It got far enough to the point that it was playable with a controller, but it had problems due to my complete lack of knowledge about how music and MIDI files worked (which to be fair, I still know little to nothing about how music works technically) so things you'd think were basic like sustains were just completely missing because I had no idea how to get the length of a sustain from a MIDI chart.
So after another year and a half (around March 2017) I decided to pick it up again. And while people seemed really hesitant at first about a new clone entering the scene, I kept working on it because I just wanted to see myself make a somewhat complete project after the numerous things I left completely broken or unfinished.
So cut to nearly a year later (December 2017), here we are where Clone Hero has somehow picked up an extremely big fanbase (relative to the amount of people still playing with their plastic guitars) and I'm somehow still adding things to the game I never thought I'd be able to do (because of lack of knowledge).
So, that's the history of CH I guess.