I think in other replies Mezzsoft mentioned they werent going to make different main mechs, but there might be different armor and engines, since theres two whole customization slots for those two things, which may change the appearance of the Crawler a bit, just a guess though!
thats cool to hear, it would be nice if the mech changed visuals depending on what weapon hes using, it might do that already but i cant notice, i really loved the game so far and cant wait for more, im hoping to see civilians or ground troops in the future, since we have horse-like martian aliens in the last mission