Upgrading the arrows and boulder is just pointless, winning with all three weapon systems should be possible and upgrading them should not set you back so far there is no hope of winning.
So you toast a pre-made pizza crust in a pan, fry all your ingredients together, dump them on the crust and then put the whole mess in the microwave. I think Mcdonald's probably had a better recipe when THEY made pizza.
I fixed it :)