LOL, I've seen a few artists do these characters, and I haven't seen one yet remember Invisigal has a sternum implant for her breathing. >snicker, snicker<
I'm guessing most artists haven't even played the game either (too busy making art and don't have the time, or it's just not their thing). They're just jumping on the bandwagon as their patrons beg for art from that franchise. Bandwagon'ing isn't bad per se, unless they get all kinds of details wrong. Stuff like that separates those who are just there to make a buck any way they can as fast as they can vs. artists who are not just good with drawing technique but also take the time to get it right (even if it is "just porn," in cases like this).