Everyone forgets the acid spit, third lung, two hearts, light sensitive skin colour changing, immunity to most poisons (so I assume poisoned weapons in the tabletop are some of the few they're _not_ immune to), etc. etc. XD

...Seriously Space Marines have a truckload of implants and powers everyone seems to forget about. XD Although at the very least I doubt the "eat brains, gain knowledge" one won't see much use here.