Unfortunately, I never managed to find cofounders that were as much motivated as I was - each one I worked with was working on it as a hobby more than anything else, and I usually had to tell them what to do, which was exhausting considering I was the only developer to develop such a big beast. Adding marketing on top of that was just too much. We still applied to Y Combinator with the last cofounder I worked with, but he wasn't really ready to move to another continent for the project and quickly started looking for excuses to drop it. He got one when we ended up not being selected :) We're still friends, but I learned that it's hard finding people to build things.
I'm still extremely proud of this project, tho. Both technically and humanly, I learnt so many things! And the project is still running without needing much maintenance, so I guess it's still a success in some way. Plus, it helped me to find jobs, since people are usually a bit impressed when you can explain to them in interview how gameboys work under the hood ... :)