There is a lot to like about the Riverside Tavern. It is a great place to go for a relaxed meal and drink; the food is excellent for both quality and choice, and prices are very reasonable.
There is a seating area outside beside the river where I ate a lovely seafood meal with friends. Inside it is more like a traditional sports bar with screens to keep you updated on a variety of sports, mostly from the US, though these screens are not obtrusive and loud (at least when I was there).
The staff are friendly and very good too. There is plentiful car parking. I will definitely head there again when next in Belize City.