Whatever goes upon 2 legs is an enemy.
The pigs start dealing with humans and end up walking on 2 legs.
Whatever goes upon four legs, or has wings, is a friend.
The pigs end up thinking any animal who walks on four legs or has wings in inferior.
No animal shall wear clothes.
The pigs all end up wearing clothes.
No animal shall sleep in a bed.
Squealer changes this to 'No animal shall sleep in a bed with sheets' because they decided to sleep on the humans beds.
No animal shall drink alcohol.
Squealer changes this to 'No animal shall drink alcohol to excess' and end up getting drunk often.
No animal shall kill any other animal.
Squealer changes this to 'No animal shall kill any other animal without cause'. Napoleon sentences anyone who was thought to be plotting against him (though he has no evidence) to death. Boxer is sent off to be killed and turned into glue when he breaks a leg.
All animals are equal.
Squealer changes this to 'All animals are equal, but some are more equal than others'. It is very obvious that the pigs come out on top and order everyone around.