device_get_tilt_z()
Returns: Real
This function returns a value between -1 and 1 depending upon
the angle of "tilt" of the device. The actual correlation between
degrees of tilt and the value returned depends on the device and OS
that it uses, but generally a value of 1 or -1 is the same as
+/-90°. The image below shows how each if the available functions
relates to the device:
y += sign(device_get_tilt_z());
The above code uses the tilt value to move the player along the y axis.