Grenadiers are in the process of being phased out, alongside zombie scientists, because they donāt represent the established lore that Kevin has stated. Theyāre being replaced by robots that have the same functions, last I checked. Whenever an āintelligentā zombie or creature is pulled for adding to the game, this is typically cited, such as the case of the zombie burner, which was originally going to use its flamethrower before this was deemed not only far too destructive but also not realistic for how the blob acted.
The blobās intelligence and coordination comes in the form of a hive mind. Individual blobs - and by extension, individual zombies - are extremely dull and possess little more than basic function. There are ābrain blobsā in slime pits that act as coordinators, but these blobs donāt control zombies themselves.
The martial arts are trained because motor controls cause your body to respond in certain ways, and the knowledge of how to use those is wired into your brain. I think of it like that the blob can access what bionics provide along with the rest of the body, but they are clearly not intelligent creatures, given the fact that they walk into obvious traps and canāt path around simple obstacles.
The Cataclysm happened from a coordinated attack by that hive mind, which had seeped into the ground water earlier before, and a nuclear exchange between the major powers, and the portals in laboratories being breached and causing acidic rain and extradimensional monsters spewing out, AND the robots being misprogrammed and shooting everything on sight, A N D the sentient fungus known as the Mycus beginning to take over everything its spores could reach. It wasnāt just a zombie apocalypse, it was a combination of every apocalypse! The fact that the blob mutated its hosts in a matter of hours didnāt help much, and nobody knew to pulp them.
People were absolutely able to wire in skills, but it was in its infancy when the Cataclysm struck. Bionics had not expanded out onto the core markets and were still available mostly for the military, who were solely unprepared against extradimensional threats that struck from within - especially when many of them were housed in the same laboratories from which the horrors stemmed. There was just no chance of escaping.
