The improvements bolster specific stats such as weapon damage, gas consumption, and anchoring distance, but the choices are somewhat simplistic. By collecting materials through cutting off specific Titan limbs and clearing objectives, you can create new weapons or enhance your blades, scabbard, and omni-directional mobility gear. But don't get too excited, because the crafting system is relatively remedial.
At the completion of most missions, you are sent to a small hub area where you can chat with some of the characters and craft and upgrade your equipment.