0        1        2        3        4        5        6
.D.MMMMM XXXXXXXX SSSSYYYY AAAAAAAA BBBBBBBB CCCCCCCC DDDDDDDD
D = If 1, player starts facing left
M = Background music; use the MusicTracks scope
X = Starting X position
S = Number of screens in the level
Y = Starting Y position
A,B,C,D = Sprite graphics slots.

7        8        9        10       11
llllllll LLLLLLLL ssssssss SSSSSSSS CCCCCCCC
l = Low byte of level data pointer
L = High byte of level data pointer
s = Low byte of sprite list pointer
S = High byte of sprite list pointer
C = Level background color

After these 12 bytes is a list of graphical resources (palettes and background tilesets) used by the level, terminated with a $ff. This list gets written to LevelUploadList.

After the graphical upload list is a 16-bit big endian word that places scrolling barriers between screens:

Bits:     a b c d e f g h i j k l m n o L
Screens: 0|1|2|3|4|5|6|7|8|9|A|B|C|D|E|F

The L bit doesn't correspond to a scroll boundary, and if it's 1 it instead signals that the level wants to link some screens together vertically. These links are in this format:

....NNNN TTTTBBBB
N = Number of screens minus one
T = Screen number the top edge links to, relative to this one
B = Screen number the bottom edge links to, relative to this one

These two bytes repeat until 16 screens have been specified.