Sonic 2 (SMS) RAM Map

$1174 (2 bytes) = Layer 1 (camera) x position
$1176 (2 bytes) = Layer 1 (camera) y position

$1295 (1 byte) = Current level
                   #$00 = Underground
                   #$01 = Sky High
                   #$02 = Aqua Lake
                   #$03 = Green Hills
                   #$04 = Gimmick Mt.
                   #$05 = Scrambled Egg
                   #$06 = Crystal Egg
                   #$07 = Ending Sequences
                   #$09 = Intro Sequence / Title Screen
$1296 (1 byte) = Current act. Notes: for the Ending Sequence, #$00 is the Bad and #$01 is the Good; for the Intro/Title, #$00 = Intro Sequence, #$01 = Title Screen.

$1298 (1 byte) = Life counter, any value above #$09 is displayed with 9

$1299 (1 byte) = Ring counter (in hexadecimal, the code jumps from #$09 to #$10 for example)

$12B9 (2 bytes) = Game timer (low byte = seconds, high byte = minutes), Sonic dies when it reaches 10 mins (in hexadecimal, the code jumps from #$09 to #$10 for example)

$12BC (1 byte) = Frame counter for game timer, adds 1 second in the clock when reaches #$3C (60 frames)

$13A9 (1 byte) = Invincibility timer, starts at #$78 decrementing each frame

$13AA (1 byte) = Frames holding button when jumping. Freezing it at some value "enables" a flighting mode

$13B4 (2 bytes) = Idle frame counter, Sonic will enter idle state when it reaches #$0200

$14A9 (1 byte?) = Frame counter for tile animation, maybe

$1501 (1 byte) = Sonic status (prev)
$1502 (1 byte) = Sonic status

$1503 (1 byte) = On ground status, kinda

$1510 (1 byte) = X subposition
$1511 (2 bytes) = X position

$1513 (1 byte) = Y subposition
$1514 (2 bytes) = Y position

$1516 (1 byte) = X subspeed
$1517 (1 byte) = X speed

$1518 (1 byte) = Y subspeed
$1519 (1 byte) = Y speed

$151A (2 bytes) = X position in screen

$151C (2 bytes) = Y position in screen

$1522 (1 byte) = Blocked status, format: 0000lrdu (l = left, r = right, d = down, u = up)
$1523 (1 byte) = Blocked status mirror, I guess

$1707 (1 byte) = Counter for updating $170E, I guess

$170E (1 byte?) = Related with Ending phase, or timer to Ending go to Game Over screen