So he let me know this morning that this was just going to be a phone interview, so I had to switch gears a bit. He downloaded a game I made and have published on the Google Play Store, and he was just kind of pleased it worked, which surprised me - I thought he'd care more about the polish. But I guess I'm just a programmer, so it doesn't matter whether it's pretty or not since it all worked.
I sent him screenshots of some of my Unreal blueprints last night (that's what I'll be working in, so he was wondering if I had experience) and he asked me to describe a difficult obstacle I overcame using blueprints, as well as to describe my process in creating them.
We talked a while back and forth in stuff like that, and I got a second interview, now in person. He said he really likes me and he thinks I'll be a good fit (and he's the lead designer, so I figure that's a good sign), but other people like the CFO need to see me and see what they think. So all in all, I think I'm doing ok!
The other interview is on Friday. He said not to dress up, but I think I'll just go with a business casual since that's how I'd be most comfortable in an interview. I'm gonna take all this advice you guys gave me for today and put it into use then. Thanks for the help!