I found these cool cheats for MAME.I dunno if this is piracy or not i will give you cheats to add in the cheat.dat

First off MK1:
Mortal Kombat (rev 5.0 T-Unit 03/19/93)
:mk:39900000:094228:0000C0F0:0000FFFF:Infinite Fatality Time:ROM Hack
:mk:00000000:20A264:00000002:0000FFFF:Get Double Flawless Bonus:This gives you a Double Flawless for each Flawless Victory
:mk:39800000:09CF68:000000FC:FFFFFFFF:Have Reptile's Speed:ROM Hack
:mk:39810000:09CF6E:000000FC:FFFFFFFF:Have Reptile's Speed (2/4)
:mk:39810000:09CF98:00000004:FFFFFFFF:Have Reptile's Speed (3/4)
:mk:39810000:09CF9E:00000004:FFFFFFFF:Have Reptile's Speed (4/4)
:mk:00000000:20A528:00000001:FFFFFFFF:Turn CPU Scorpion into Reptile
:mk:00000001:20A2BC:00000000:FFFFFFFF:Die Now! PL2:This makes the player die almost immediately
:mk:00010001:20A30C:00000002:000000FF:Die Now! PL2 (2/2)
Note:more cheats are in the cheat.dat
Mortal Kombat (rev 1.0 08/09/92)
:mkla1:39900000:093EB2:0000C0F0:0000FFFF:Infinite Fatality Time:ROM Hack
:mkla1:00000000:209A08:00000002:0000FFFF:Get Double Flawless Bonus:This gives you a Double Flawless for each Flawless Victory
:mkla1:39800000:09C61A:000000FC:FFFFFFFF:Have Reptile's Speed:ROM Hack
:mkla1:39810000:09C620:000000FC:FFFFFFFF:Have Reptile's Speed (2/4)
:mkla1:39810000:09C64A:00000004:FFFFFFFF:Have Reptile's Speed (3/4)
:mkla1:39810000:09C650:00000004:FFFFFFFF:Have Reptile's Speed (4/4)
:mkla1:00000001:209A60:00000000:FFFFFFFF:Die Now! PL2:This makes the player die almost immediately
:mkla1:00010001:209AB0:00000002:000000FF:Die Now! PL2 (2/2)
Mortal Kombat (rev 2.0 08/18/92)
:mkla2:39900000:093E84:0000C0F0:0000FFFF:Infinite Fatality Time:ROM Hack
:mkla2:00000000:209A08:00000002:0000FFFF:Get Double Flawless Bonus:This gives you a Double Flawless for each Flawless Victory
:mkla2:39800000:09C6F6:000000FC:FFFFFFFF:Have Reptile's Speed:ROM Hack
:mkla2:39810000:09C6FC:000000FC:FFFFFFFF:Have Reptile's Speed (2/4)
:mkla2:39810000:09C726:00000004:FFFFFFFF:Have Reptile's Speed (3/4)
:mkla2:39810000:09C72C:00000004:FFFFFFFF:Have Reptile's Speed (4/4)
:mkla2:00000001:209A60:00000000:FFFFFFFF:Die Now! PL2:This makes the player die almost immediately
:mkla2:00010001:209AB0:00000002:000000FF:Die Now! PL2 (2/2)
Mortal Kombat (rev 3.0 08/31/92)
mkla3:39900000:09420E:0000C0F0:0000FFFF:Infinite Fatality Time:ROM Hack
:mkla3:00000000:209A08:00000002:0000FFFF:Get Double Flawless Bonus:This gives you a Double Flawless for each Flawless Victory
:mkla3:39800000:09CF0E:000000FC:FFFFFFFF:Have Reptile's Speed:ROM Hack
:mkla3:39810000:09CF14:000000FC:FFFFFFFF:Have Reptile's Speed (2/4)
:mkla3:39810000:09CF3E:00000004:FFFFFFFF:Have Reptile's Speed (3/4)
:mkla3:39810000:09CF44:00000004:FFFFFFFF:Have Reptile's Speed (4/4)
:mkla3:00000000:209CCC:00000001:FFFFFFFF:Turn CPU Scorpion into Reptile
:mkla3:00000001:209A60:00000000:FFFFFFFF:Die Now! PL2:This makes the player die almost immediately
:mkla3:00010001:209AB0:00000002:000000FF:Die Now! PL2 (2/2)
Mortal Kombat (rev 4.0 09/28/92)
:mkla4:39900000:09422C:0000C0F0:0000FFFF:Infinite Fatality Time:ROM Hack
:mkla4:00000000:209A08:00000002:0000FFFF:Get Double Flawless Bonus:This gives you a Double Flawless for each Flawless Victory
:mkla4:39800000:09CF70:000000FC:FFFFFFFF:Have Reptile's Speed:ROM Hack
:mkla4:39810000:09CF76:000000FC:FFFFFFFF:Have Reptile's Speed (2/4)
:mkla4:39810000:09CFA0:00000004:FFFFFFFF:Have Reptile's Speed (3/4)
:mkla4:39810000:09CFA6:00000004:FFFFFFFF:Have Reptile's Speed (4/4)
:mkla4:00000000:209CCC:00000001:FFFFFFFF:Turn CPU Scorpion into Reptile
:mkla4:00000001:209A60:00000000:FFFFFFFF:Die Now! PL2:This makes the player die almost immediately
:mkla4:00010001:209AB0:00000002:000000FF:Die Now! PL2 (2/2)
Mortal Kombat (rev 4.0 T-Unit 02/11/93)
:mkr4:39900000:09423A:0000C0F0:0000FFFF:Infinite Fatality Time:ROM Hack
:mkr4:00000000:20A264:00000002:0000FFFF:Get Double Flawless Bonus:This gives you a Double Flawless for each Flawless Victory
:mkr4:39800000:09CF7A:000000FC:FFFFFFFF:Have Reptile's Speed:ROM Hack
:mkr4:39810000:09CF80:000000FC:FFFFFFFF:Have Reptile's Speed (2/4)
:mkr4:39810000:09CFAA:00000004:FFFFFFFF:Have Reptile's Speed (3/4)
:mkr4:39810000:09CFB0:00000004:FFFFFFFF:Have Reptile's Speed (4/4)
:mkr4:00000000:20A528:00000001:FFFFFFFF:Turn CPU Scorpion into Reptile
:mkr4:00000001:20A2BC:00000000:FFFFFFFF:Die Now! PL2:This makes the player die almost immediately
:mkr4:00010001:20A30C:00000002:000000FF:Die Now! PL2 (2/2)
Mortal Kombat (prototype, rev 9.0 07/28/92)
:mkprot9:39900000:093DE2:0000C0F0:0000FFFF:Infinite Fatality Time:ROM Hack
:mkprot9:00000000:209A04:00000002:0000FFFF:Get Double Flawless Bonus
:mkprot9:39800000:09C11A:000000FC:FFFFFFFF:Have Reptile's Speed:ROM Hack
:mkprot9:39810000:09C120:000000FC:FFFFFFFF:Have Reptile's Speed (2/4)
:mkprot9:39810000:09C14A:00000004:FFFFFFFF:Have Reptile's Speed (3/4)
:mkprot9:39810000:09C150:00000004:FFFFFFFF:Have Reptile's Speed (4/4)
:mkprot9:00000001:209A5C:00000000:FFFFFFFF:Die Now! PL2:This makes the player die almost immediately
:mkprot9:00010001:209AAC:00000002:000000FF:Die Now! PL2 (2/2)
Mortal Kombat (Yawdim bootleg)
Note:Get the latest cheat.dat to enable these cheats
:mkyawdim:39900000:09420E:0000C0F0:0000FFFF:Infinite Fatality Time:ROM Hack
:mkyawdim:00000000:00209A08:00000002:0000FFFF:Get Double Flawless Bonus:This gives you a Double Flawless for each Flawless Victory
:mkyawdim:39800000:09CF0E:000000FC:FFFFFFFF:Have Reptile's Speed:ROM Hack
:mkyawdim:39810000:09CF14:000000FC:FFFFFFFF:Have Reptile's Speed (2/4)
:mkyawdim:39810000:09CF3E:00000004:FFFFFFFF:Have Reptile's Speed (3/4)
:mkyawdim:39810000:09CF44:00000004:FFFFFFFF:Have Reptile's Speed (4/4)
:mkyawdim:00000000:209CCC:00000001:FFFFFFFF:Turn CPU Scorpion into Reptile
:mkyawdim:00000001:209A60:00000000:FFFFFFFF:Die Now! PL2:This makes the player die almost immediately
:mkyawdim:00010001:209AB0:00000002:000000FF:Die Now! PL2 (2/2)
There that should do it for MK1