All food sold in Brunei is halal. There is no alcohol available anywhere in the country — officially, at least. Non-Muslim visitors may bring a limited personal allowance of alcohol through customs for private consumption, but you will not find it in restaurants, hotels, or shops.
The national dish, if there is one, is ambuyat — a sticky, translucent paste made from sago starch, eaten by twirling it around a bamboo fork and dipping it into a tangy sauce called cacah, often served alongside fried fish, beef rendang, or vegetables. It is an acquired texture but worth trying at least once.
More immediately approachable is nasi katok: a simple plate of steamed rice, fried chicken, and sambal chilli available from small stalls and kiosks around the clock for a dollar or two. It is the everyday meal of Brunei and impossible to get wrong.
The hawker food scene in Bandar Seri Begawan draws on Malay, Chinese, and Indian traditions. Rice and noodle dishes dominate. Roti canai with curry, laksa in a coconut broth, and various noodle soups are all easy to find. The night markets are the best places to eat affordably and sample the range.
Given Brunei's significant Chinese population, Chinese-Malaysian food is widely available — particularly in towns like Kuala Belait. The food culture is less celebrated than in neighboring Malaysia or Singapore, but it is genuinely good and extremely affordable. Eating out is cheap by any measure: a proper meal rarely costs more than a few Brunei dollars.