When you exceed level 3 (0x43+) for an underground level, it proceeds to the castle levels, then JUNK DATA When you exceed level 21 (0x36+) for an overworld level, it proceeds to the underground levels, then the castle levels, then JUNK DATA (3-4 is the last possible level that would appear as a water level) When you exceed level 3 (0x03+) for a water level, it proceeds to the overworld levels, then the underground levels, then the castle levels. If the level number is between 60 and 7F, it's a castle level. If the level number is between 40 and 5F, it's an underground level If the level number is between 20 and 3F, it's an overworld level If the level number is between 00 and 1F, it's a water level. (Ignore the top bit for now, treat 80-FF as the same as 00-7F) Why do you get lots of variations of existing levels with the wrong world type? Then it will load some out-of-range level number afterwards.Īt this point, you're just getting random data from other parts of ROM being treated as a level number. It won't pick one of these 8 numbers: 0, 5, 10, 14, 19, 23, 27, 33Īnd instead, it will pick some other data as a starting number for level table. Now what happens if the world number is invalid? Looking good so far, we have a table of valid world numbers, and valid level numbers.

Level 0圆2 appears as both World 2-4, and World 5-4.

Level 0x27 appears as both World 2-3, and World 7-3. Level 0x01 appears as both World 2-2, and World 7-2. Level 0圆0 appears as both World 1-4, and World 6-4. Level 0x26 appears as both World 1-3, and World 5-3. db 0x33, 0x29, 0x01, 0x27, 0圆4įrom looking at the table we can see this: It lists all the level numbers of the game. Then there is a level table for the 8 worlds. The contents of the table begin with 0, then you add either 5 or 4 to the number, depending on whether there was a pipe transition level or not. So now we have a World Number, and an Area Number.įirst there is a small table (8 bytes long) to find a 'Level List Index' for the level list. (1 is added to this number when it is displayed)īecause world 1-2, 2-2, 4-2, and 7-2 begin with an animation where Mario enters a pipe, those worlds have 5 areas instead of 4. Here is how Super Mario Bros 1 level numbers work.ħ5C = Displayed number after the dash (Only used for display, and making world 5 harder once you reach 5-3)ħ5F = WorldNumber, 0 to 7.

Super mario bros world 0-1