Hi! I tried your game and it was very fun! Here is your feedback:
I was playing on a Macbook with the trackpad in the browser.
1. On Classic it was cheap; I didn't die and my health points only went down to 180 approximately.
2. The pistol, auto-shotgun, and the rifle were the strongest (or: the rifle was the most overpowered). On the other hand, the sniper and crossbow feel meh (not unsatisfying, but the other weapons overshadow them). P.S.: Rocket feels nice, but the rifle was really overpowered.
3. The workshop was clear, although maybe the grenades feel unnecessary when you get the rocket.
4. Performance was good: no lag, no errors, etc.
For me it is a great game; maybe you can add some enemy radar as an upgrade or an anti-personnel mine to make traps in big waves. :-)