I created a prototype which was uploaded earlier in the year, I have added a few changes including ammo piles, less boulders and a better scoring system.

The plan is to destroy the boulders as quick as you can... but be careful with your ammo! Each wave 10 more boulders are spawned.

I have put all of the code (impact allows me too) onto my website for you to see how I made it :)

If you have any feedback or new idea let me know!

Cheers, Stu