They run just as fast as you when they don't teleport to your general vicinity. They have unlimited ammo and health. They predict your next FOM and raise dead soldiers to fight like zombies. Sure im bitching, but that crap just isn't why I play metal gear...

Obligatory edit: near unlimited health, so non lethal play is not an option as far as I know

Edit 2: Its just my opinion, I prefer expert soldiers than mutants. More realistic play is my passion, and mgs has a good combo, the skulls just push it too far for me.

Edit 3: Teleporting ....if you guys support that for regular enemies in a mgs game then more power to you, but for you to prove or even suggest that this is a good inclusion...shoot in that case have fun!

Final edit/tl; dr double header: apparently every single encounter with them are considered boss encounters, tho you can't tranq them like most bosses in mgs... And im using the wrong weapons and I need to git gud. Yay!