What level do higher difficulties unlock?

[SNAKE †]

I'm currently level 8 but can only do amateur still, what level do I have to be to increase difficulty? and also are the asylum and high school maps the only new maps to unlock

[Biggles]

Level 10 unlocks Intermediate, Level 15 unlocks Professional.
AFAIK yes, those are currently the only new maps.

[Some Kinda Kobold]

Looking at the Road Map. 3 new levels are planned so far. Apartments, Prison and Mansion. No idea how long it'll take, though. Considering all the praise and players this game has attracted. I wouldn't be surprised if the dev team grew.

[Boshedo]

I'll give this Dev my full praise. He is active on the forums. That says a lot about other Devs in Beta Games. Its one reason why I bought this game because the Dev participates on the forums. He's a one man crew so he is trying his hardest to cater to everyone. I expect there to be a lot more content in the near future.