sophistikate
One thing I would like to ask about:
I'm about to leave my job to go full-time for this start up but I'm not leaving my job on good terms. Will this be a big deal? I feel like by the time I apply in a few years, this job will be such a small part of my story that it won't even matter. Long story short, I felt really disrespected at this company and was treated poorly so I started performing poorly and basically am playing a waiting game (I have to stay 1 year or else I give back my signing bonus).
All else equal, leaving on better terms is more desirable. That said, this could also be apart of the story you tell in your application. You started at a company, but you realized your passions were something else (if that is true; don't lie if this is not the case). Then you dedicated/shifted your career to your startup. It could also be that you realized how much potential there was in the market for your startup, so you did it because of that.
During interviews, you could be asked why you decided to leave that company. You can always spin it (though I would not make up any lies), but parting ways on good, or at least neutral terms would be better.
Did you ever talk with HR, your manager, or whomever you felt disrespected you? If not, you probably should have.
Feel free to PM me if you want.