We've had so many contests now, it's about time someone compiled a list of all the rules that have been thought up. This may be inspiration for anyone thinking of rules for future contests. Of course, it's okay to repeat a rule from an old contest -- that will give people who missed out on the old contest another chance to come up with something.

There were three unofficial contests, before the numbered official contests started. Lemmix was used for these, so the first contest refers to the original 8 skills.

1 - Make a level with one of each skill

2 - Make a level in the crystal style with no builders

3 - Make a level with 5 or fewer lemmings

The first eight official contests only had a single rule each:

1 - Make a level using an unofficial tileset

2 - Make a Fun/Tame level

3 - Tag Team (one person designs the terrain, the other places objects and assigns stats)

4 - Make a level with exactly 5 total skills

5 - Make a level with a save requirement at most 10%

6 - Make a level with no constructive skills

7 - Make a level with at least 4 exits

8 - Make a level with a L2 or L3 style

Contest #9 was the abortive "here are three rules, try to loophole one of them", which attracted no entries, but led to the three-rule format followed by all subsequent contests. (Note that this contest was ignored in the numbering, so the next contest is *also* numberered 9.) An asterisk before a rule indicates a repeat or near-repeat of a rule from an earlier contest.

*Rules from the "loophole" contest:*

R1 - Make a level with at most 12 (terrain pieces + objects), with at most 4 being objects

R2 - Make a level where all terrain is steel that requires at least two destructive skills to solve

R3 - Make a level using exactly the terrain + objects of an original Lemmings level

9R1 - Make a level with only new skills

9R2 - Make a level with only one lemming

9R3 - Make a level with exactly two types of skill

10R1 - Make a level with no permanent skills

*10R2 - Make a Fun/Tame level

10R3 - Make a level with at least two new object types

11R1 - Make a level with save 2/2, at most 1 of each permanent skill

11R2 - Make a level with 1 of each provided skill

*11R3 - Make a level with no constructive skills

12R1 - Make a level with a time limit of 1min or less

12R2 - Make a level with no destructive skills

12R3 - Make a VGASPEC level

13R1 - Make a level with tileset mixing

13R2 - Make a level with at least two intended solutions

*13R3 - Make a level without using any official tilesets

14R1 - Make a level with 3 hatches and 3 lemmings

14R2 - Make a level with no steel and 2 hatches

14R3 - Make a level with exactly 2 of any 8 skills

15R1 - Make two levels with the same terrain, but one is flipped

15R2 - Make a minimal-size level with at most 10 lemmings

*15R3 - Make a level with only new skills

16R1 - Make a level with height at least 3 times its width

16R2 - Make a level with at most 2 minutes and hatch-exit distance at least 2 screens

16R3 - Make a level with at least 3 hatches, save requirement (h-1)/h * 100%

17R1 - Make a level using only tilesets you haven't used before

17R2 - Make a level with exactly 1 type of skill from each category

17R3 - Make a level with only one type of terrain piece

18R1 - Make a level with one hatch, one exit and no other objects

18R2 - Make a subset of an official level

*18R3 - Make a level with at most two types of skill

19R1 - Make a level with at most 3 non-permanent skills

19R2 - Make a level whose terrain spells your username

19R3 - Make a level with exactly 1 lemming and save requirement at least 2

20R1 - Make a level with horizontally and vertically symmetrical terrain

20R2 - Make a level with at least 10 skill types, at most 5 of each

20R3 - Make a fake "disjoint union"

21R1 - Make a level using at least 3 jumpers

21R2 - Make a level with one hatch, at least two exits, and each exit must be limited to an equal share of the save requirement

21R3 - Make a level depicting a recognisable character, object or landmark

22R1 - Make a level using only original skills and objects

22R2 - Make a level using only new skills and objects

22R3 - Make a level with at least one neutral and at least one zombie

23R1 - Make an X-of-everything level for X at most 10

*23R2 - Make a minimal-size level with at most 10 lemmings

23R3 - Make a level divided into two sections, one tileset in each

24R1 - Make a level with exactly one new skill type

24R2 - Make a level at least 200,000 pixels large

24R3 - Make a level with a rule from a previous contest

25R1 - Make a level with only preplaced lemmings, and no two having the same permanent skills

25R2 - Make a level with at most 10 terrain pieces and at most 10 objects

25R3 - Make a level that depicts a physical object

26R1 - Make a level with no destructible terrain

26R2 - Make a level with infinitely many jumpers

26R3 - Make a level with only L2 tilesets and L2 skills

27R1 - Make a level with only constructive skills and bombers

27R2 - Make a level in which all lemmings are pre-assigned swimmers (in NL) or runners (in Lix)

27R3 - Make a level with RR 99 and at most 10 lemmings

28R1 - Make a level with an entrance near each corner and the exit in the centre

28R2 - Make a level depicting an animal

*28R3 - Make a minimal-size level with at most 9 lemmings and at most 9 skills

29R1 - Make a level with three hatches on one side and the exit on the other

29R2 - Make a level depicting a vehicle

29R3 - Make a level with at least three linked teleporters (in NL) or flingers (in Lix)

*30R1 - Make a level using a single tileset you haven't used before

30R2 - Make a level with only destructive skills

30R3 - Make a level in the l2_classic style using only the classic 8 skills and classic objects