15 is indeed tricky. You release the triangle and the 2 trucks so they can pass each other, and open the block so they can push the black square. Leave the triangle to the end, it seems to work that way. The star pushesh you to the platform and it falls by itlself to slide you to the goal.
Great idea but overall gameplay feels lacking. Also, a tutorial would be nice. It took me some time to figure out what was going on and how to reroute trains and evade crashes.
This game is broken. You carry your money to the next level - you reach the enemy base and stop building units to accumulate cash. You start the next level with 25-30k and just mass a wave of catapults for quick victory. I didn't even build any of the the units after catapult.
I agree that lvl14 seems impossible. I have 3 plinter guns and 1 manual gun without upgrades and the bow pattern that spawns i made of extremely tough ships and they are so close !
I never got the SF games. Only fighting game that could keep me semi-interested was MK3 Ultimate.
Try down-forward-S for hadouken and croucking kicks when they get near.