Completely open source! With special zero-latency debouncing code that keeps the switches from glitching out. Mouse code, models, pcb design, and build guide:
https://github.com/wareya/DIY-Gaming-...
SROM ripping code (Arudino IDE, arduino-pico board type):
https://gist.github.com/wareya/0dc349...

3d printing skill highly recommended!

Here's an excellent, very well-researched video about the electrical reasons why double clicking problems are so much more common than they used to be:
   • Failing switch problem: Omron vs the ...  

Music used:
"Speedier Than Photons" by Joth https://opengameart.org/content/speed...
"Enchanted Tiki 86" by cynicmusic https://opengameart.org/content/encha...
"Gone Fishin'" by Memoraphile @ You're Perfect Studio https://opengameart.org/content/gone-...
"Rewind" by Pro Sensory https://opengameart.org/content/rewind
"Chill Lofi R" by omfgdude https://opengameart.org/content/chill...
"Next to You" by Joth https://opengameart.org/content/next-...
"It Takes A Hero" by Zane Little Music https://opengameart.org/content/it-ta...