The top panel contains a duct that conceals two 120mm exhaust fans. As seen in the picture, the duct can be remove to facilitate placement for a dual 120mm radiator for water cooling purposes.

Two fan filters can be found below the case, one for for the power supply and one for the sole 120mm intake fan.

Front view with the door

and the front deal without the door! The door is easily removable via a plastic catch.

Bay panels are also easily removable via a catch. There is a total of 5 5.25" bays as you can see, with a 3.5" conversion bracket provided.