That plane was a top secret german plane that did exist.
When soldiers of the U.S. Third Army arrived at the Gothaer Waggonfabrik factory at Friedrichsrode in April 1945, they found five of these futuristic jet-propelled flying wing fighters under construction.

The prototype had flown two months earlier, and although it was destroyed and its pilot killed on its third flight when an engine failed, the project pressed ahead.

Based on the ninth tailless aircraft design of Reimar and Walter Horten and assigned to Gotha for production, this twinjet fighter-bomber would have given Allied pilots a nasty shock.

Its ultramodern appearance, very heavy armament, and extraordinary speed make it the subject of some of the most exciting 'what-if' scenarios of WWII aviation.

Go 229A-0 specifications
Weight:
  11,170/19,840 lbs
  (5,077/9,018 kg)
Span:
  55ft 0.625in (16.78 m)
Length:
  24ft 60.125in (7.47 m)
Engine:
  Two Junkers 109-004B turbojets
  with 1,984 lb. (900 kg)
  thrust each
Armament:
  Four 30-mm MK 103 cannon
    with 120 r.p.g.
  Optional: two 2,205-lb.
    (1,000-kg) bombs

Max speed @ altitude:
  607 mph (977 km/h)
  @ 39,370 ft (12,000 m)
Ceiling:
  52,500 ft (16,000 m)
Initial climb rate:
  4,330 ft/min (1,320 m/min)
Range:
  1,180 mi (1,900 km)"

CFS3 takes place in the European Theater of WW2 using real missions. This game does have a nice twist. What you do during your campaign determains the out come of WW2 in Europe.

Hope that helps!

Another interesting peice of information. The Gothe/Horton Go229 is what inspired the Avro Car, the World's first functional (well not so functional) flying car. The tailless design and thin rounded wing gave designers at Avro Canada the idea that they could build a similar aircraft with a totally round O-shaped wing. This lesser known project was shadowed by the CF-105 Arrow and disapeared after Black Friday. Reports mentioned that this car might still be in the possession of the USAF.
The Go229's design would also be the insperation for the B-2 Spirit Bomber nearly four decades later.

What confuses me is how did the aircraft compensate for rudder control which it surely could not have if it was tailless?

Biggles...

Biggles, thats a simple answer, it couldn't.  The third time one was flown, very late in the war, the pilot was coming in for a landing when one of the engines died.  He was two low to bail out, so he tried to get control of the plane, but with no rudder he couldn't.  After a few mins of struggling with the controls, it started spinning down.  He made a big hole killing him and destroying the airplane.  You can thank the History Channel for that answer.