Stopped in here for a dinner while taking a long weekend in Long Beach. The exterior and interior decor doesn't look like a whole lot, but the food was wonderful and the service excellent.
For appertif, the wife and I ordered the chowder, and for entrees I ordered the Cajun Jambalaya (in Washington state, who knew??) while she had mussels. We were both VERY pleased with our meals, as well as the service.
There's no dress requirement, but I would suggest slacks for men (or your best jeans) and a collared shirt. You'll get a seat without one, but I would have felt more comfortable with one.
The only detraction - and it's a personal one - was the harp music. The owner, Cheri, plays the harp in the dining room on Sunday nights. Dinner music is okay, but it was just a slight bit too loud for me.