Is it unbiased ?

it's an accurate summary of the scholarship of the times but it gets the Schlieffen Plan and 3rd Ypres wrong. Most books do too but these are mistakes not bent history.

Marlon, Claudia and Dimby the cats 1989-2005, 2007 and 2010.

It revolves more towards the allied and british side but that's expected. As far as bias goes, I'm nowhere near knowledgeable enough to analyse that but it certainly didn't feel annoyingly biased to me.