The level (player level / profile level) is your constant level that raises by earning enough experience with killing beasts, bossbeasts, recycle modules or win maps (not all maps give experience). By higher levels you´ll unlock new buildings, modules or elements in the skillstar. Also you can unlock special maps for your grinding process.
The In-Game playprofile level is indepent of the tutorial level.
The basic factor of the needed experience is 1,8.
Example: For level two you´ll need 10 experience. After you reach 10 experience it gets multiplied by 1,8 (+ previous value) so you´ll need 28 experience for level three.