Dining Rec's - Wilmington, DE
Yeesh! Can't think of anything really good nearby that fit the bill. Probably the best would be this place; http://www.orillastapasbar.com/main/o....
It's in a block on Market St. that's a little run down, but don't let that stop you! Very creative and tasty tapas style dishes and entrees. The menu is on the website above...
Orillas is probably the only ethnic restaurant worth heading to in downtown Wilmington, although it is more on the fine-dining (tapas) end of the spectrum than you may want. The very closest restaurant to your hotel is Deep Blue (seafood)--other people like this place although I do not. The second closest place is the one I recommend most, Domaine Hudson--fine dining although very friendly, and the food and wine are excellent. Actually, Washington St. Ale House, a basic pub with food, is even closer, but that doesn't really address your stated requirements. If you go there, the food is fine as long as you don't get too ambitious about what you order.
If you get in the car you will have many more choices. The best seafood around is at Harry's Seafood Grill, maybe a mile away at the Riverfront Market. There are other little places in there also, but the rest of them are only open in the daytime.