In the Still Alive promo, there's a clip of the silhouette of Lumpy and the reindeer flying through the sky, across the screen. This clip is changed in the episode, instead Splendid is in view, the silhouettes are smaller, and Lumpy doesn't make it all the way across the screen.
Mime's death is similar to Lumpy and Pop's deaths in Spare Tire.
Cuddles' injury before death is similar to Petunia's deaths in From Hero to Eternity and Wrath of Con, since all of these instances involve getting horizontally sliced in half by Splendid's heat vision.
David Winn's voice is sampled for Splendid when he gets up after the sleigh crash.
Dana Belben and Ellen Connell's voices were sampled in this episode for the voice of Petunia.
There are a few minor differences between the storyboard and the episode. In the storyboard:
Lumpy landed on a rock.
Lumpy dies after screaming over his beard being torn off.
Petunia has scratches on her face from the fireplace explosion. (Though they heavily resemble whiskers)
Mime has a bored expression of his face when he's sitting on the log, in the episode he looks very sad.
There would have been a point of view shot of the inside of the sack when Splendid searches for Mime's gift.
Mime punching the bag caused it to deflate.
Cuddles fell forward upon being sliced in half.
Splendid was shown grabbing Cuddles' basket and tearing off his ears.