The tapas bars inside Alcudia's old walls are a different experience from the waterfront restaurants. These are neighbourhood places, used by people who live in the old town, and while they welcome visitors readily enough they haven't adjusted their offer substantially to accommodate them. The menus are in Spanish, the wine is poured in small glasses without ceremony, and the food — patatas bravas, croquetas, pan con tomate, a daily changing selection of cold cuts and cheese — is straightforward and good.
Prices are low by the standards of what you'd pay by the beach: two people can eat well on tapas and a bottle of local wine for under €30. The old town's main street and the square around Sant Jaume church have the densest concentration of options, and bar-hopping between two or three of them over an evening is a pleasant way to spend a few hours. Most bars do a menú del día at lunchtime — two courses and a drink for a fixed price — which is the best value eating in the area.
Evening service tends to start later than northern Europeans expect: kitchens get going around eight and run until midnight. If you arrive at six and wonder where everyone is, come back at nine.