The premis of a good game is there. The tank handles like a tank, and the graphics are really pretty good.
Why a 1 then? There are some major missing elements.
The biggest problem is that to play again, you need to reload. This could be a firefox bug, having to reload the page every time was super frustrating.
The cannon firs in an arc which is great, but without even a centre reticle I felt like I was just shooting randomly.
I like that the tank gets damages in water, but powerups and enemy AI need to know that. I watched enemy tanks drive into and get stuck in water only to have there power ups grop there once I had killed them. If the tank had a magentic feild that pulled in powerups once they were in range, this would be solved.
Overall this game needs some tweeks. It could be great and there isn't a lot of work, but at time of writing, there are enough negitives to make it not that much fun.
Please update when you get the chance, would love to see a fuller version of this. :)