First game: Scarier atmosphere, lasts longer (one night lasting EXACTLY 8 minutes and 37 seconds) and whether Golden Freddy will appear or not keeps the player tensed, alert, and scared.
Second game: 10 main animatronics could kill you instead of 4 (I say main because there isn't much sign of Golden Freddy, but him included makes 11), keeps you alert on the See More music box, or else the puppet you kill you, Freddy Fazbear mask doesn't work on all animatronics... BIG problem if your flashlight runs out, Oh and there's the fact that there are ZERO DOORS!
BAe is marionette
Second game: 10 main animatronics could kill you instead of 4 (I say main because there isn't much sign of Golden Freddy, but him included makes 11), keeps you alert on the See More music box, or else the puppet you kill you, Freddy Fazbear mask doesn't work on all animatronics... BIG problem if your flashlight runs out, Oh and there's the fact that there are ZERO DOORS!
You figure it out for yourself.