Created for land development, with just one of his massively powerful arms he can lift a boulder the size of his whole body. His body is made of a super-sturdy alloy, making him one tough customer!
The strategy for GutsMan is simple. Stay close and continue pelting him with attacks until he goes down while making sure to back up whenever he readies a GutsBlock/Rock to throw at you.
GutsMan's other hazard is this - when he jumps and lands, the weight of his body sends a shockwave which will stun you and leave you on your butt. To avoid this, just make sure you time your jump to be pretty much the exact time right before he lands.
Lastly, GutsMan's Digger Arm allows him to go underground and then come up under you for an attack! To avoid it, just make sure that when you see the earth trembling beneath your feet you get out of there ASAP!