I think it was the facepalm of these eps that may have contributed to my giving up on the show when i was 12. Otherwise, the eps just looked stunning.
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I definitely noticed this, even as a child. The first badly animated episode is The Terror of Hammerhand. Now, this is obviously my opinion, though I find the degradation in animation quality so obvious that I would challenge anyone who disagrees.
Next up is the episode Sixth Sense, it looks so bad that I can't bear to watch it and will always skip that episode on the DVD. It's a shame because it's not even a great episode anyway, I feel that good animation could have saved it slightly.
Next one I recall is the mind power trial episodes with Tygra. (The Trial of Evil is also badly animated) there are probably others but the further I get into the series, the less I can recall outright. Again, I personally find such episodes unwatchable.
Compare these episodes with the likes of "The Time Capsule," "The Ghost Warrior" or "The Rock Giant" They are stunning. Unfortunately it's hard to find reasons for all this and most people don't seem to recognise the difference in quality although I see it so blatantly.
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I noticed it too. Sometimes multiple animation studios are contracted to work on the same series because there is too much work for one studio to complete in the time allowed. A minimum of 65 episodes were usually required for an animated series to be broadcast daily.
The differences in animation styles were really noticeable on
The Transformers
. The first season and most of Season 2 were animated by Toei in Japan, but some of Season 2, much of Season 3, and all of Season 4 featured lower quality animation by the South Korean studio AKOM. The third season episode "Call of the Primitives" had a distinctive style that did not resemble the work of either Toei or AKOM. At least eight different studios provided animation for
Batman: The Animated Series
, which is why the look of the series varied quite a bit. Sometimes part one of a two-part episode would be animated by one studio while part two would be done by another, with obvious differences in appearance. AKOM was one of the studios that worked on the first season of
Batman
but they were fired because the quality of their animation was deemed substandard.