VGFacts

The very first teaser image for the game showed a slightly different design for Springtrap.


Teaser:


Final Game:


Here are the differences I noticed:

• Nose is lower placed and differently shaped
  
• Eyelids look almost angry in the teaser
  
• Different Teeth (Sharp and possibly bloody)
  
• He's not grinning
  

BONUS TRIVIA!
(May contain spoilers)
[spoiler]
One of the rare boot up screens, which features Springtrap removing his head, is very similar to a poster of Feddy removing his head that would rarely appears in one of the halls in the original Five Nights at Freddy's.


[/spoiler]