Pros
If you’re a recent college computer science graduate and you need something relevant for your resume, then Code Particle is probably fine for a year or so. Don’t stick around longer than that, though, and do your own research about good architecture and implementation practices instead of listening to the bad advice of the founders (but do the bad practices they tell you to while you’re working for them so you have a chance of getting a decent reference from them when you leave).
Cons
Of the three founders, only one is a competent engineer. The other two both think they’re the greatest coders who have ever lived, but their code quality is terrible, both from an architecture and an implementation perspective, and they refuse to listen to anyone’s ideas. They should stick to managing the business (which is what they’re actually good at). Basically, they’re wanna-be game developers who are frustrated that they aren’t good enough coders to make it in video games, so when they hire anyone who’s actually better at software engineering than they are, it tickles their insecurities.