The timeline bugs me, here are the problems reconciling the TV series with the prequel OVAS:
Chirico's personality. In the first episode of the TV series, Chirico sounded like a normal guy, then come the prequel OV As Red Shoulder Document: Roots of Treachery and Pailsen Files, where he's the psuedo-paranoid calmly aware Stoic war veteran we know and love.
The Diving Beetle. Gotho during the Kummen arc claimed it was a new model, yet in Pailsen Files episode 1, the Giglamesh forces were using it, what gives?
Chrirco in Sunsa. He claimed that he was not in Sunsa doing war crimes, and come Red Shoulder Document: Roots of Treachery, he was there, twice, first, he survived a massacre there, and went there the second time, but not burning villages to the ground. And that reminds me...
Pailsen in Sunsa. He wasn't there in Sunsa during Chirico's flashbacks in Red Shoulder Document: Roots of Treachery, now come Phantom Arc, where he was there, witnessing Chirico's Abnormal Survivor skills.
How could Giglamesh still have an army after what happened in Planet Monad, where all 120 million Giglamesh troops were wiped out, despite in the TV series, where they still had an army for the ends of the Uoodo and Kummen arcs.
Rochina/ Luske. How could the higher-ups in the Giglamesh military not recognize Rochina as Wockam's aide, since they've seen him with Wockam, then again, Luske claimed his name will disappear, but still...