Ganamae said:
well like to know what Lucas was thinking when he added the wrong arm and so much blood...
The blood is easy to explain: they hadn’t yet come up with the idea that a lightsaber cut cauterizes the wound and prevents bleeding. I think they came up with that idea when filming ESB so Luke wouldn’t be suffering massive blood loss during his final confrontation with Vader.
Perhaps that’s something that should have been corrected for ANH-97 or -04. Whatever.