I tried playing this twice. The first level worked fine, then the next level was completely black. I refreshed the page, and the level worked fine, until I died, and when I tried to restart the level, it was like a screenshot of my death moment had been captured and I could not see the actual level. Fix the issues with it, and then MAYBE I'll consider trying again.
ENGINEER IS CREDIT TO TEAM
That's all there is to say.
A challenging but rewarding game.
The latter levels require quite a bit of strategy. Zerging for panels without first gathering resources and laying down defences will get you killed very quickly. For the last level against the final boss I had to barricade myself with three walls of cheap gun turrets, while forcing all the robots to zerg into the only opening - filled with rockets, flame throwers and EMPs. It was a tough fight, but I sure enjoyed it!
Pretty good game, but
There is one things that you might consider. First the scrap idea is good but it tends to make the player have to go after them and into danger, maybe a magnet tower to pull in near by scraps and have upgrades that boost the range.
I can't comment on the game because I couldn't play it due to there being no quality change button and the default graphics make the game run too slow to play, I see in other reviews that people also have the same problem.
My advice would be to implement a quality change button with low/med/high/best and then hopefully we will get to give your game an actual rating.