You won't be included in the decision making or planning process even if you are a primary developer. After discussing this with an owner, my concerns were brushed off. Get ready to play guessing games with your roadmap, and be blind sided by marketing requests such as public demos while still in preproduction. This was odd given the small company size.
They won't hire an IT guy. Get ready to fix your machine, other people's machines, and maintain several servers should you need them.
The company is very focused on game scripting in UnrealScript, so it might not be a good place for Juniors as that is an obsolete skill.