Python

Rule I & III (34 chars)

print'Uryyb Jbeyq'.decode('rot13')

Rule I & III, alternative (39 chars)

print"\110e\154\154o %cor\154\144"%~-88

Rule II & III (37 chars)

input("H\x65ll\x64 W\x64%cld"%(3*38))

Rule I and II (50 chars)

input('\x48\x65\x6c\x6c\x6f \x57\x6f\x72\x6c\x64')

All three rules (58 chars)

input("\x48\x65\x6c\x6c\x6f %c\x6f%c\x6c\x64"%(84+3,3*38))

Python

Rule I & III (34 chars)

print'Uryyb Jbeyq'.decode('rot13')

Rule I & III, alternative (39 chars)

print"\110e\154\154o %cor\154\144"%~-88

Rule II & III (37 chars)

input("H\x65ll\x64 W\x64%cld"%(3*38))

Rule I and II (50 chars)

input('\x48\x65\x6c\x6c\x6f \x57\x6f\x72\x6c\x64')

All three rules (58 chars)

input("\x48\x65\x6c\x6c\x6f %c\x6f%c\x6c\x64"%(84+3,3*38))

Python

Rule I & III (34 chars)

print'Uryyb Jbeyq'.decode('rot13')

Rule I & III, alternative (36 chars)

print"\110e\154\154o %corl\144"%~-88

Rule II & III (37 chars)

input("H\x65ll\x64 W\x64%cld"%(3*38))

Rule I and II (50 chars)

input('\x48\x65\x6c\x6c\x6f \x57\x6f\x72\x6c\x64')

All three rules (58 chars)

input("\x48\x65\x6c\x6c\x6f %c\x6f%c\x6c\x64"%(84+3,3*38))

Python

Rule I & III (34 chars)

print'Uryyb Jbeyq'.decode('rot13')

Rule I & III, alternative (39 chars)

print"\110e\154\154o %cor\154\144"%~-88

Rule II & III (37 chars)

input("H\x65ll\x64 W\x64%cld"%(3*38))

Rule I and II (50 chars)

input('\x48\x65\x6c\x6c\x6f \x57\x6f\x72\x6c\x64')

All three rules (58 chars)

input("\x48\x65\x6c\x6c\x6f %c\x6f%c\x6c\x64"%(84+3,3*38))