@2stupid2dothis When Port 1 and Port 2 device types are set to "Auto" in Quick Menu -> Controls (RetroArch menu), the emulator puts a regular NES controller in port 1 and an Arkanoid controller in port 2. You can use a mouse as the Arkanoid controller in this configuration.

If you want to use a controller's D-pad instead, you can set Port 1 and Port 2 device types to "Gamepad."