Their ships and tech is much an open book and there was plenty of room to create there but in a lot of ways they made huge deviations and I don't see how they can claim the game is canon where the Gorn are concerned.
Much of the Gorn is an open book and I don't see anything that really conflicts with on-screen material so much that you can't work around it.
Where to start? For one they are an Alpha Quadrant power and considered Cestus III part of their territory, not from some far off Galaxy or even a far off quadrant like the Gamma quadrant only accessible through a worm hole/rift. Sorry they are the Dominion.
Their history is unknown but clearly in was in the Milky Way and Alpha Quadrant to boot so they weren't galaxy conquering expansionist as in all the history through Deep Space Nine and Voyager were they even mentioned, let alone engaged in some galactic war to control the Milky Way or even the Alpha quadrant. So all canonical history shows them to be what was portrayed in Arena as territorial xenophobes who simply attacked because they though their space was being invaded.
Of course physiologically their were wild deviations. The Gorn in Arena, or even the ENT epsiode, In A Mirror Darkly were not portrayed as quick or agile. The game got their immense strength and durability right but turned them into raptors instead of the stolid plodding creatures in the tv series. Only the Gorn Champion was an accurate representation.
They only areas were they could have taken huge license to change was the tech and ships as they have been unseen.