How the Tess Was Won - August 5, 1956 - S1-E5
Continuity mistake: Though he's leaped into someone else, we always see Sam as Sam, dressed in all the host's clothes (including glasses or sunglasses). His host is revealed only in reflections. But here, when he looks at his host-self in the mirror, the hat and clothes are all identical - except that the reflection is wearing glasses, and Sam isn't. (00:43:00)
Genesis (1) - September 13, 1956 - S1-E1
Continuity mistake: When Al is standing next to the juke box, Sam walks over to make a selection, and when Al starts talking his reflection is visible on the glass. Later in this episode, Sam is talking to Al at the sink of the dressing room at the ball park. As Sam looks into the mirror he says he thinks Al is a vampire, to which Al replies, "Neurological holograms don't reflect, Sam." (00:26:00 - 01:15:30)
Genesis (1) - September 13, 1956 - S1-E1
Continuity mistake: The shaving cream smeared on Sam's face looks nothing at all like the cream on his reflection's (Tom's) face in the mirror. (00:08:00)
Genesis (1) - September 13, 1956 - S1-E1
Continuity mistake: A confused Sam/Tom stumbles out into the yard bare-chested with shaving cream smeared on his face and neck. In the next shot, though he hasn't touched it, the cream is suddenly all over his chest as well.
The Color of Truth - August 8, 1955 - S1-E7
Continuity mistake: After Miss Melanie's son leaves, Sam/Jessie reaches out to steady her. His left hand is on her shoulder until the camera angle changes, when both his hands are at his sides. Change angles again, and his hand is back on her shoulder.
The Color of Truth - August 8, 1955 - S1-E7
Continuity mistake: When Sam leaves the jail after the Sheriff has released him from custody, we can see Sam's reflection, not Jesse Tyler's, in the window on the door as it swings shut behind Sam.
Genesis (1) - September 13, 1956 - S1-E1
Continuity mistake: In the shower, the Burma Shave cream on Sam's face changes from being partially washed off to being thick and foamy, then back to partially washed off.
Genesis (1) - September 13, 1956 - S1-E1
Continuity mistake: Al casts a shadow on the airplane. That's should not occur, since Al is a hologram. (00:50:05)
Genesis (2) - September 13, 1956 - S1-E2
Continuity mistake: When Sam ejects from the X-2 and parachutes to safety, he lands on the desert floor and the chute comes down on top of him, covering him completely. In the very next shot, we see him lying face up and the parachute has entirely disappeared.
The Right Hand of God - October 24, 1974 - S1-E4
Continuity mistake: Near the beginning, Sam has a cut on his left eye from the fight which they apply a bandage to later. The cut briefly disappears when Sam is talking to the sister, only to reappear.
Genesis (1) - September 13, 1956 - S1-E1
Continuity mistake: Al is talking to Sam near the hanger about his options regarding the pilot. When we see Sam and the back of Al's head, there is a significant shadow on Al. It isn't there in the opposite angle. On top of that, since Al is a hologram, shadows shouldn't affect him.
Play It Again, Seymour - April 14, 1953 - S1-E9
Continuity mistake: The cut on Sam's face from the bullet is larger than the one on his counterpart's face.
Answer: Sam threw items off the raft to lighten the load, so it wouldn't sink, in doing so he made the raft less heavy. Which made easier to float with the currents, if it was heavy the raft would have moved slower and not moved so far.
Except that Al said that immediately after throwing stuff out of the boat four hours passed and it was shown that they didn't really move from where they were. They were still in the same spot. Forgot to ask this too. When Sam and Vanessa are stranded on the island, one of them, can't remember who, did something and when Al appears, he tells them that because of it, time had suddenly skipped several more hours and if the event hadn't been interrupted, they would have been rescued by a boat. So, what happened on the island that once again caused time to speed up? It seems kind of strange that time could move so quickly on the island, especially since it was still day time and it never showed any sort of changes like the sun or clouds moving.