On the VS screen (in 2 player mode), you can cycle through the 6 symbols. The numbers 
below are the number of times you need to change the symbol.

911-911 - Armless Kombat
020-020 - Blocking Disabled
090-090 - Breakers Disabled
022-022 - Dark Kombat
001-001 - Disable Foreground Objects
391-193 - Double Dash
222-555 - Dream Kombat
051-150 - Enhanced Moves Disabled
227-227 - Explosive Kombat
012-012 - Health Recovery
808-808 - Headless Kombat 
091-091 - Hyper Fighting
770-770 - Invisible Kombat
831-831 - Jumping Disabled
101-101 - Klassic Music
931-931 - Kombos Disabled
900-900 - No Blood
110-000 - Player 1 Half Health
000-110 - Player 2 Half Health
220-000 - Player 1 Quarter Health
000-220 - Player 2 Quarter Health
404-404 - Power Bars Disabled
707-707 - Psycho Kombat 
303-303 - Quick Uppercut Recovery
234-234 - Rainbow Kombat
717?313 ? Random Phrase 1: ?Don?t defend in a temple corrupted with shadow.?
448?844 ? Random Phrase 2: ?The krypt walls hold secrets.?
122?221 ? Random Phrase 2: ?What lurks at the bottom of The Pit??
009?009 ? Random Phrase 2: ??SUNOB YTSAOT?
550?055 ? Random Phrase 2: ?Who hides in the forest??
031?130 ? Random Phrase 2: ?Motaro Transformation??
282?282 ? Random Phrase 2: ?She waits for you at the top of the tower??
123?926 ? Random Phrase 2: ?Thanks for karing!?
044-440 - Sans Power
300-300 - Silent Kombat
731-731 - Specials Disabled
123-123 - Super Recovery
010-010 - Throwing Encouraged
100-100 - Throwing Disabled
111-111 - Tournament Mode
466-466 - Unlimited Super Meter
424-424 - Vampire Kombat
242-242 - X-Rays Disabled
666-666 - Zombie Kombat