This is a list of Vehicles. Feel free to use it to brainstorm about how vehicles should work.
Somehow, customising your weapon would be nice. There's a way to do that fairly easily.
Equiped like armor, takes away most mining and crafting functions, but turns you into a huge battle-ready mech. Your fists are guns!
Alright, so guns on fists wasn't enough for you? How about being 5 meters tall and having guns on your fists. More powerful guns, as well.
Crawls on 8 legs, and absolutely huge. This thing is the size of a small town.