That's the dreadnoughts, which are sometimes portrayed with the occupant's head literally sticking out the front like the mech "suits" from Kill la Kill. The terminators are supposed to just be particularly heavy suits of power armor, but the art gets kind of silly because they originated with model kits that were kind of silly and had wacky proportions because GW's original sculptors favored extreme stylization over accurate details because of the limitations of the old mold production processes before they made it big and started being able to have plastic injection molds made in the early 2000s.
That's the dreadnoughts, which are sometimes portrayed with the occupant's head literally sticking out the front like the mech "suits" from Kill la Kill. The terminators are supposed to just be particularly heavy suits of power armor, but the art gets kind of silly because they originated with model kits that were kind of silly and had wacky proportions because GW's original sculptors favored extreme stylization over accurate details because of the limitations of the old mold production processes before they made it big and started being able to have plastic injection molds made in the early 2000s.