Here comes the list of games that I know about:

• 3D Achterbahn-Simulator
• 3D Action Spiele - Compilation - includes the following games (some are shareware versions):
  • Acid Moon
  • BiShoot
  • Blast
  • Bomberman Carnaged
  • Crazy Ball Game
  • Die Hölle auf Erden
  • Freischuss
  • Hainrich
  • Hide the Bodies!
  • Lach isch oder was?
  • Ocean City 2
  • Race
  • Ruprecht
  • Schafjagd
  • Snake Clone
  • Sopwith 3D
  • Superku
  • Tales of Awernia
  • Bang Ball
  • War Train
• 3D Fahrschule
• 3D Hunting: Extreme
• 3D Hunting: Grizzly
• 3D Hunting: Shark
• 3D Hunting: Trophy Game
• 3D Hunting: Trophy Whitetail
• ACK3D Games: technically not Acknex games, but these games are using the ACK engine, which was later modified by JCL into the Acknex engine:
  • Station Escape
  • H.U.R.L.
• Airborne Hero - D-Day Frontline 1944
• Angst - Rahz's Revenge
• Bang Ball
• Block iX
• Boss Hunter
• Der Name des Bruders
• Fang die Maus
• Feuerwehr 3D
• Glider - Collect'n Kill
• Hades II
• Hostradamus
• IncrediBubble
• Kabus 22
• Kroko-Mania 3D
• Lost Idols
• Magic Mahjongg 3D
• Matchball Tennis
• Memoria Würfel
• Ocean City Nemesis
• PacFish
• Panzer Offensive - Westfront 1940 - 1945
• Panzerfront Barbarossa 1941 - 1945
• Panzeroffensive Afrika - Wüstensturm 1941 - 1943
• Pikto
• Ploing 2
• RC Boat Challenge
• Replics
• Replics III - Behind the Light
• Saints of Virtue
• Sammy Suricate
• Segeln - Deutsche Inseln: Nordsee und Ostsee
• Segeln 2007
• Skaphander (Virus Explosion, Explosion 3D)
• Spike the Hedgehog
• Terminal Machine
• The Varginha Incident (Alien Anarchy)
• USA Bass Championship
• W.A.R. Soldier
• War Train - Normandie 1944
• Winthorp’s Mansion
• World War II - Battlefield 1939 - 1945
• Wrong Turn
• Yoddha the Warrior

For more games not listed here try AUM, the forum or the Wayback Machine. The old Gamestudio website had links to released games.

If I made a mistake and a game on this list was not made with Gamestudio please correct me. It would also be very nice, if anyone with knowledge could name all the missing games that aren't listed.