I beg you add 1 huge mountable gun on top of the crawlers chassis, like the juggernauts from the anime/manga 86. I would balance it to have a mag of 3-5 rounds, apfsds if possible that can be fired quickly doing around the same damage as the rail gun only without the penetration through buildings/enemy's.
Your game holds a really special place in my heart I wish you the best of luck in coding it.