In terms of copyright and public perception, the game genre is irrelevant. What is relevant is that both titles will have the "stargate" moniker and thus both games will be considered, by the public, as coming from the same franchise (which is true).

And since the original copyright owners have no control over what un-licensed people do with that copyright, even if they made a side-scroller to avoid confusion with the MMOG, it would still carry the "Stargate" name and thus still be a problem.

Copyrights: easy to learn; a lifetime to master!