name the episode

IIRC, the two episodes to check are:
"Point of No Return": During the ISN report on the Alexander and fellow defector's escape, an Omega either fires a a red beam (ie. x-ray laser) from the side or is hit by one. I'm pretty sure it fires said beam, someone with the DVDs will have to check.
"No Surrender, No Retreat": During a view of the battle from a Whitestar's bridge window, a red beam (ie. x-ray laser) can be seen originating from an Omega's forward ventral area, aft of the hammer head.
Personally, I prefer the defence grid being a lot more proactive and effective in the game than the TV series. On the show, it's been shown to be quite capable when it's actually given enough of the budget for rendering. I think the idea that it's too effective in the game comes from a false impression given by the TV series, which tends not to show the defence grid donig much of anything (or missing widely against Whitestars at point-blank range). The game should not be held to such an artifact of budgetary limitations.