Tank treads only sometimes work without invulnerability, invuln. recommended.
On my PC, 20% and lower speeds run well, results may vary
(Controls in [brackets] means on num pad)
At start of game, press -, = to expand treads, Z to tighten reloader
Left tank treads: : forwards : reverse
Right tank treads: : forwards : reverse
T to raise, G to lower.
Press and hold L to launch. For beginner use, hold L until shuttle stops moving. (For rapid fire, hold L until shuttle reenters barrel, then tap L to slow shuttle to quickly let it come to a rest near rear of gun.) Briefly hold H to reload, Repeat!
(Optional, toggle C to pull shuttle towards rear of gun)
Up, down, left, right, to aim
Pres and hold  to fire, when grabber reaches front, press [.], remain holding  til grabber stops, release.
Second bomb is  to fire,  to release
[*] to rotate, [-], [+] to raise and lower
1,2,3,4,5 (not on numpad) to fire
Flame plow: Comma key to lower, period key to raise. Y to activate flamethrowers
Light Tank ("Rakhiot") has very similar cannon, is campaign legal and runs on higher speed.