Evil-Lyn's cape is missing when she casts her spell on the Spellstone at the start, and again when uses it at the Royal Palace.
When Man-At-Arm uses the remote control for his weather controlling satellite, his hands are flesh colored instead of green in one shot. Additionally, his green "gloves" have fingernails.
Before Evil-Lyn transforms herself into the old woman (Zenia), her gauntlets are missing and Skeletor's back-straps are gone in the overhead shot.
Around the 12 and a half minute mark, after Skeletor says "The others lead to destruction", Trap Jaw's jaw-piece is colored green like his face instead of magenta like his helmet.
King Randor describes how the Creeping Horak would grow over an entire house and squeeze all the air out, killing the inhabitants. This would explain why the Eternians are unable to use any exits to escape from the palace when the Horak is after them. However, around 17 and a half minutes in, the outside of the palace is shown and there is no sign of the Creeping Horak covering it.
Randor, Marlena, Teela, Man-At-Arms and Orko run through the palace and end up in the last room not engulfed by the Creeping Horac but we never see if there are any other palace guards or servants in trouble.