Character design differences between episodes

[simon's ghost]

I especially noticed a change between episodes 12 & 13 of 2nd Gig, but I'm sure I remember noticing it earlier too, even in the 1st season. Is it because of a personel switch? or are some episodes drawn simultaneously by different people?

[miki-chan]

There's also quite clearly a different animation crew that did "Natural Enemy," "PU 239," and "Trial." (I think they do mention this in the interviews on the DVDs, but I forget precisely who worked on which episode, and I'm too lazy to go look again... )

[GhostLine]

i sure it all comes down to who's the key animator of a particular episode....