Island Strikz bowling alley has an excellent sports bar with above average food. Pass Road about 100 yards into Gulfport.
Mugshots is across from the mall. It's good too.
Hooters on the beach is also good.
The casinos are not good places to watch games, although there may be a few casino bars that I don't know about that are good for games. Las Vegas has sports book and is a great town to watch a game in a casino, but no sports book in Biloxi. Also, there are not as many non-casino bars in Biloxi as there used to be. It's not always easy to find a place.
Of all of these, I like Island Strikz the best. You are smart to have wanted to get out of the casino for the game. I hope, though, that you were lucky enough to miss it altogether.