Initialised by the routine at 8684, and used by the routines at 870E, 8ABB, 8BDD and 8D05. Possible values are:

Value	Meaning
0x00	Willy is neither falling nor jumping
0x01	Willy is jumping
0x02-0x0B	Willy is falling, and can land safely
0x0C+	Willy is falling, and has fallen too far to land safely (see 8BDD)
0xFF	Willy has collided with a nasty or a guardian (see 8D05)