Infamous Adventures remade King's Quest III in 2006, but their version was closer to a 1:1 remake of the Sierra original, while AGDI's remake is a continuation of the expanded King's Quest II: Romancing the Stones storyline from our previous KQ remake.
If it helps, you can think of AGDI's KQ2+ and KQ3 Redux as being one long game that's meant to be joined together. Redux carries over the unique elements of our writer, Daniel Stacey's, unique (non-canon) plot.
As to why we started a KQ3 remake when one had already been made, we had already been working on our version for 2 years (albeit, in secret) when IA announced theirs, and we didn't want to throw away all the work.
You can read more about the reasoning for this in Erpy's first post of the KQ3 Redux History thread on
our KQ3 Redux forum here.
