+1 on "the Undead". Creepy to the max.
Loved the "Angry Red Planet". They managed to keep the sci fi comic book vibe, all action adventure with mysteries left unsolved.
Forbidden Planet was the A film of the genre, and still is with "It the Terror From Beyond Space" and "Angry Red Planet" as B+.
If you haven't seen "Journey to the Seventh Planet" give it a chance. The story is above average and could stand a remake.
"Night of the Blood Beast" is better than you'd think. Hidden in the horror aspect is a pretty good story, actually a bit into the modern style. Aliens grimly set on saving Earthlings from extinction if they have to kill us all in the process.