Here's an idea of how far I will go for something as trivial as this list. I had to watch Plan 9 not once, but TWICE to get these errors down! The word "obviously" comes up a lot in this list, and only because I feel it is necessary to point out how obvious some of the flaws are.
In case you couldn't tell [translation: in case you're blinder than a bat!], the errors are numbered, and after the numbers is the approximate time into the movie the error BEGINS to occur. Some errors last only a split-second, while others last several minutes.
[0:00:14] Jump cut
[0:00:31] Criswell redundancy: "Future events such as these will affect you in the future."
[0:01:16] Criswell is obviously reading a cue card.
[0:02:45] The priest at the funeral never opens his mouth to say a word.
[0:04:15] The controls in the cockpit are obviously fake.
[0:04:46] Boom mic shadow is easily seen.
[0:05:42] The string holding the flying saucer is visible.
[0:05:50 and MANY other occurrences] The flying saucers wobble as if being hung by a string.
[0:06:00] Stock footage shows a completely different cemetery.
[0:06:27] It's dark in the cemetery, but the sun shines outside of the cemetery.
[0:07:00] Criswell redundancy: "The grief...became greater and greater agony."
[0:07:09] Criswell redundancy: "The home that they shared together..."
[0:08:02] Criswell redundancy: "...never to return again."
[0:08:03] When Bela Lugosi walks off the screen, it's obviously a freeze frame--the swaying tree suddenly freezes.
[0:08:03] Even though the old man walks into the street and gets hit by a car, his shadow is still on the ground!
[0:08:19] Criswell hesitates, as if he momentarily loses his place on the cue card.
[0:08:20] Isn't the old man's wife rather young for him?
[0:08:39] A man at the old man's funeral says that it's "getting dark." GETTING?? It's already pitch black!
[0:08:49] A woman at the funeral screams--and by gum, the sound travels so slow that it picks up in mid-scream!
[0:09:13] Night changes to day.
[0:09:25] Day changes to night.
[0:09:25] Seems to me that the tombstones are WAY too close together for there to be room for bodies!
[0:09:39] Clay briefly forgets his line: "Medical, uhhh....examiner been 'round yet?"
[0:10:10] Really bad jump cut.
[0:12:21] "You mean the kind [of flying saucers] from up there?" No, you dumb***k, the OTHER kind of flying saucers!!!!
[0:12:27] Jeff describes the flying saucers as "cigar-shaped!" (For those of you who haven't seen the movie--they're saucer-shaped!)
[0:13:13] A strong wind from the flying saucer's exhaust is strong enough to blow Jeff and Paula to the ground, but not strong enough to move their hair!
[0:13:35] Someone trips over a tombstone and causes it to wobble.
[0:14:28] The zombi-fied old man is obviously a stand-in for Bela Lugosi, as a) he has more hair than Bela did, b) he's much taller, c) he's thinner, and d) holds his cape over his face to [very badly] hide the fact that he's NOT Bela! [This stand-in will from here on be referred to as "Dr. Tom."]
[0:15:13] Zombie Vampira flinches when Inspector Clay fires at her.
[0:16:07] The detective scratches himself with the barrel of his loaded gun.
[0:16:50] The priest at Clay's funeral is obviously reading from a cue card.
[0:18:10] The flying saucer is flying low. REALLY low.
[0:19:10] The rockets seem to all explode in exactly the same place in the sky, with the power and longevity of exploding firecrackers.
[0:20:01] There’s a small mysterious black piece of fuzz in the "sky."
[0:20:38] An example of Ed Wood's trademarked idiotic dialog: "Visits? That would indicate visitors!"
[0:21:42] The planet is obviously an inflatable toy.
[0:21:55] Criswell makes a brief--and useless--narration: "What will be their next move?"
[0:22:44] The leader of the so-called advanced race of aliens completely misuses the word "resurrection."
[0:23:27] Why does the leader use earth days when instructing on when to meet him again?
[0:24:19] The flying saucers cast HUGE shadows as they leave their "planet."
[0:28:10] Day changes to night.
[0:31:49] Night changes to day.
[0:32:39] Two different screams come from Paula's mouth at the same time!
[0:32:55] Zombie Clay struggles to get out of his grave.
[0:32:58] Bad film edit.
[0:33:50] Dr. Tom makes a tombstone wobble.
[0:34:02 - 0:35:53] Day/night inconsistency -- TEN TIMES!
[0:37:05] Clay, who's supposed to be 100% dead [??] while the electrode gun isn't on him, blinks his eyes.
[0:38:07] Jump cut.
[0:40:17] While Kelton is in Clay's opened grave, the tombstone that fell in a few scenes earlier isn't there.
[0:40:17] Clay was obviously NOT"six feet under," as when Kelton stands up, he's only knee-deep.
[0:43:35] How did that reverb effect get on Eros's voice during the recording?
[0:43:55] Redundancy: "Eons of your years ago..."
[0:45:03] "Atmospheric conditions in outer space..." HUH????
[0:48:43] "Electrode" gun implies that it has no mechanical parts. So how can it jam? And if Eros and his race are supposedly so far advanced, why don't they design a gun that WON'T jam????
[0:49:13] The re-deadened Clay's shoulders move as he breathes.
[0:49:30] Clay blinks.
[0:51:21] The flying saucers are making noise--IN OUTER SPACE!!
[0:51:33] Thanks to a bad edit, a car materializes out of nowhere.
[0:51:44] Day changes to night.
[0:52:50] Colonel Edwards arrives at Jeff and Paula's house with the detective, but he wasn't in the car when it pulled up!
[0:54:54] After knocking out Kelton, Dr. Tom adjusts his cape.
[0:55:14] After Dr. Tom disintegrates, all that's left is his cape. Does that mean that the old man was buried nude except for a cape?
[0:58:41] It's four o'clock when Jeff and the detective enter the ship. How do we know this? There's a CLOCK on the wall inside!
[1:01:50] When the inner door of the spaceship opens, light shines on the wall. But when the outer door is open, Jeff and the detective look into total darkness.
[1:05:33] Eros calls a firecracker a "harmless explosive," despite the fact that thousands of people get seriously injured by them.
[1:05:59] Eros flubs his line.
[1:10:00] Eros says that his race doesn't "cling to life." Then why is he so hung up about saving everybody?
[1:11:20] One window inside the spaceship shows a cloudy afternoon sky. The window next to it shows darkness.
[1:13:21] Why does the zombie Clay get distracted when hit by a stick, yet bullets don't seem to bother him?
[1:17:25] Criswell obviously reads from a cue card.