The Season Pass will contain 6 DLC packs, each containing a unique themed mission level with story and free play modes. (jamiex66.com)
Although 8 mission levels sounds small you'll find that each mission, depending on how much you actually do, can take up to 2 hours or so each. (cogconnected.com)
The difficulty is easy enough if you attempt to keep your level scaled well next to the required mission level, however boss battles can be challenging and can often require you to plan a strategy instead of rushing into battle during the heat of the moment. (gearnuke.com)