Koopaloop's Mountain Controls Steam Controller (2015) about 1 year
combined playtime All necessary controls including music! Hold right-grip and use gyro to rotate view. Left trackpad, left thumbstick and ABXY buttons play music.
Mouse Inputs Keyboard Inputs Gyro Inputs Touch Menus
Mountain Nintendo Switch Pro about 10 hours
combined playtime Controller option for Mountain. Check out Mode Shifting for D-pad, Right Stick, Left Stick, and Triggers for all piano notes. Also Mode Shifting on BAXY for window size options.
Keyboard Inputs Mode Shifts Gamepad Inputs