The Return of the Beast: Part 1 - S1-E1
Continuity mistake: When Banner is strapped to the chair and trying to resist transforming into the Hulk, the extent to how much he has transformed varies. Some shots will show his hands and head becoming larger, and the next shot will show him to instantly be back to normal proportions.
The Return of the Beast: Part 1 - S1-E1
Continuity mistake: When General Ross is warning Banner that he is not bulletproof, an armed guard is flanked on either side of Banner. When the shot changes, the guard on Banner's left had suddenly moved several feet away.
The Return of the Beast: Part 1 - S1-E1
Continuity mistake: When Rick is telling his boss that he needs to leave work to help out a friend in a jam, he is standing next to the payphone, and when the shot changes, he is already several feet away sitting on his motorcycle and putting his helmet on.
The Return of the Beast: Part 1 - S1-E1
Continuity mistake: When the Hulk is trapped inside the containment unit and Betty calms him down, once he has reverted back to Bruce Banner, his hair is shown being blonde instead of brown.
The Return of the Beast: Part 1 - S1-E1
Continuity mistake: When General Ross is talking to Betty about the danger the Hulk presents to the world, the distance between them differs depending on the shot. One shot shows them standing close enough to hug each other, the next shot shows them instantly at arms' length apart.
The Return of the Beast: Part 2 - S1-E2
Continuity mistake: When the Leader is preparing to force Banner to transform into the Hulk, he shoots Gargoyle in the left shoulder with a blaster for being insolent, which leaves a hole in the corresponding area of his clothing. Moments later, the hole has disappeared.
The Return of the Beast: Part 2 - S1-E2
Continuity mistake: When Betty and Rick are attacked by the giant scorpion, the other mutated desert creatures appear perched on the humvee from out of nowhere.
The Return of the Beast: Part 2 - S1-E2
Continuity mistake: When Thunderbolt Ross is talking about cutting a star out of the Hulk's hide, he is leaning against what remains of a wall after a hole was torn through it. When the shot changes to the Leader watching Ross through his insect drone, the section of the wall that was directly in front of Ross is now missing.
The Return of the Beast: Part 2 - S1-E2
Continuity mistake: When the Hulk is fighting the army helicopters in the desert, the color of the sky and the position of the sun indicate that it is twilight. When the Hulk takes cover in the canyon, the sun is setting at an unrealistically rapid pace. It transitions from twilight to nighttime faster than the helicopters can travel a quarter mile.
The Return of the Beast: Part 2 - S1-E2
Continuity mistake: When Talbot asks Betty why she is always helping the Hulk, they are standing next to a pipeline. When the shot changes, they have instantly moved several feet away from it.
Helping Hands, Iron Fist - S1-E4
Continuity mistake: Early in the Hulk's fight with Iron Man, he punches Iron Man onto the hood of a red car and then throws a blue car at him. Iron Man disappears from the screen as soon as the blue car hits the red car, and then can be seen either back on the hood, or instantly inside the car. If he is still on the hood, then he disappears from the screen once again when Hulk throws the car.
Helping Hands, Iron Fist - S1-E4
Continuity mistake: When Hulk punches Iron Man into the bus, Iron Man is shown landing through the roof in the middle third of the bus on the driver's side. When the shot changes to Iron Man inside the bus, the hole in the roof is now shown to be down the center of the bus and closer to the front.
Helping Hands, Iron Fist - S1-E4
Continuity mistake: After Rick Jones finds Bruce Banner among the overpass wreckage, Bruce starts transforming into the Hulk and grabs some gray rubble, which immediately turns the same color as his flesh.
Helping Hands, Iron Fist - S1-E4
Continuity mistake: When Rick Jones is hanging on to the containment unit that the Hulk is trapped inside, at one point the Iron Man gauntlet that he borrowed switches from his right hand to his left.
Helping Hands, Iron Fist - S1-E4
Continuity mistake: When Doc Samson is carrying the cylindrical tank for the nutrient bath, he is holding it from the bottom rim. When the shot changes, he is holding it from the outside.
Continuity mistake: When Bruce Banner is in the soup kitchen, there are several paneled windows behind him. When he is shown standing up from his seat, it is only a brick wall behind him.
Answer: I believe it was mentioned in an issue of Wizard Magazine that the show was cancelled because of low ratings, and reportedly the show's creative shift in the second season had a part to play in the low ratings, as the changes alienated fans.
Phaneron ★