Yes well, this is more the rom-hacking part. It's nice and all, and google kills me with romhacking replies, but I'm talking about running info. I think GameGenie or Gameshark or something like that does the same thing.
I'll give some examples...
In SMB1,
0x0057 contains the current running speed
0x001D indicates your falling state
0x009F is your vertical speed
0x0002 is your height
0x0500-0x05CF is a map layout
0x07F8-0x07FA is the time
0x075E continains your coin-count
0x07DE-0x07E2 is your score
0x07D8-0x07DC is the hi-score
In 3D worldrunner (blatant copy/paste coming ;),
0024 - 0025 = input flags?
002E = horizontal position (proving the game is 255 units or positions wide)
0035 = direction. 00 = forward. FF = backward
005D = how high up in the air... offsets at 0 when on the ground, moves up/down by 2. you can fire when this value <= 2 going or staying down. once jumping, you have one frame to fire.
0065 = airborne (0=no, 1=yes)
007c = 0A means uncontrollable...
0083 = some kind of count down when fired, doesnt seem to impact gameplay... start at 28 every shot
0092 = new life state: 0 = starting game (reset) / nothing (just alive), 224 = gameover, 128 = unmoveable (like coming onscreen new game) until 0, 112 = dying until 128
00A8 = some kind of forward position
00C0 = see 00A8
00D0 = distance of current shot. you can not fire when this is >0, and it reaches 0 before the last shot leaves the visual range. gets reset immediately when hitting an enemy.
00D9 = something about height as well, but offsets at 181 when on the ground and decreases as you go up. there are more addresses like this one in the 02xx range
00E0 = number of lifes
0603 - 0608 = (value-0x30) is score, xxxxxx, where 100's = 0606, 1000's = 0604 etc. when the counter ticks at 999900, 0607's lowbyte turns to 9 as well (only time ever). after that no increments are possible. game doesn't use the 0608 lowbyte, but you can set them all to 9 to get the game to show 999999 as score :) what the 0x30 represents I can't tell.
06C0 - 070F = indicates land, where "you" seem to be on 070D E or F and 06C0 is at the horizon. only lowbytes are used, E means land, 4 means gap.
And finally Excitebike (another paste from my own docs),
0408-040f = timer (f=low 8=high). counts 0 to 10 each
03d4 = some kind of vert pos, not quite though
00b0 = which track you are in, 1-4 (0 means sand etc). luke says "when in the air" :s
049x-04fx = track picture, use for collision stuff
03e3 = motor temp. starts at 08. stables at 17 when holding A. overheats at 32. running over "speedup" actually just resets your temp (kind of misleading...)
03ac = 2=down, 1 moves towards the moter a little bit (how much?), 0 doesnt move towards the motor/on the motor/...
037c = 0:ok, 1:puddle, 2:top/bottom of track (1 and 2 = slowdown)
0627 - 062C = score (low nibbles make up score)
08f3 = speed. starting at 0, maxes at 46/47. pressing B gets you there faster (increments by 2, where A adds just one), but 47/49 seems the max speed. seems to be a cap somewhere, poking it higher doesnt give you more speed.
0090 = vertical position (out of context of game)
000e = i think this is 1 when your standing still and are ready to go, 0 else
0024 & 0034 = count down at start. 0034 starts at 5 counts down every 11 frames then 0024 starts to count down once per frame, when 0024 is at 2, it means go (why 2?)
Its stuff like this I'm looking for. This is usefull for a bot. Romhacks are generally not. So...