Even the best dump of Batman Arkham City Wii U has quirks. Here are fixes for common problems.
Playing the Batman: Arkham City Wii U ROM requires a few steps: batman arkham city wii u rom
This means your ROM is incomplete. You are missing the meta folder. You need a "Loadiine ready" ROM, not a raw dump. The meta folder tells Cemu the required firmware version. Even the best dump of Batman Arkham City Wii U has quirks
Furthermore, the game made extensive use of the Wii U GamePad. In an era before the Switch normalized second-screen gaming, Arkham City used the controller to display the map, manage WayneTech upgrades, and even serve as the interface for hacking and solving Riddler puzzles. For many, the ROM format is the only way to faithfully replicate this dual-screen experience on modern hardware via emulators like Cemu. You are missing the meta folder