I imagine this to be a bomber. It ain't flashy, pretty, or fast, but it can sure drop the hurt. The pilot and navigator sit in the forward cockpit with the sensors, radar, and imaging in the pod next to them. The bombardier and targeting crew sit in the topside cockpit. The payload is lowered in through the central dorsal compartment. The powerful port and starboard engines drive this heavy thumper while the aft thrusters are reserved for pouring on the speed to get the hell out once the job is done. Individual crews will take to painting symbols and insignia on the various paneling, although the only sanctioned markings are numerals and call-signs. This one is fresh off the factory floor, hence the lack of identifiers.
As others have said, it does have elements reminiscent of the Millennium Falcon like the front prong things and the offset bridge/cockpit looking segment. That dark grey door/hatch looking thing in the middle on top there also reminds me of the hangar door on the Bebop from Cowboy Bebop.
Nice work! Very reminiscent of Ralf McQuaries' work. The original concept artist for Star Wars Episodes 4, 5 & 6. Reminds me of the Millennium Falcon in a way, almost like a variant of the original design. Again, Nice Work!