Here are the comparisons I'm making:
http://fallout.wikia.com/wiki/Marcus
http://fallout.wikia.com/wiki/Fawkes
http://fallout.wikia.com/wiki/Securitron
http://fallout.wikia.com/wiki/Protectron
http://fallout.wikia.com/wiki/Remnants_power_armor
http://fallout.wikia.com/wiki/Enclave_Power_Armor_(Fallout_3)
I am also looking at the geckos, the trees, and the Strip itself. They just seem to follow a different more cartoon-ish art style, to me.