Initialised by the routine at 34762, checked by the routines at 35591, 36796 and 38344, updated by the routines at 37046, 37310 and 38064, and checked and updated by the routines at 36307, 36564 and 38098. Possible values are:

Value	Meaning
0	Willy is neither falling nor jumping
1	Willy is jumping
2-11	Willy is falling, and can land safely
12-15	Willy is falling, and has fallen too far to land safely
255	Willy has collided with a nasty, an arrow, a guardian, or Maria (see 37046)