Good start. The technical basics are all there, to go pro quality just make sure the puzzles make sense, get good art all over, make sure the puzzles make sense, add a little bit of length, make sure the puzzles make sense, verify that you can see everything on a dim monitor, make sure the puzzles make sense, and add a little plot.
Oh, and for gods sake, don't do what most people do- make sure the puzzles make sense.
Yeah, not marking this down 'cuz it took a long time to load. Marking this down 'cuz of bad voice acting, poorly implemented text handling, and losing progress when going to a menu.
Third browser crash- 2/5. I don't think there's a way to fix the physics issues without a new physics engine. (BOUNCY steel girders that only break at the HINGES?) Needs: rigid hinges, and a good modeling of deformation.
Fix the collision detection and secondary explosions. Why do the plus-looking things square shaped for collision detection, and why are little things overlapping them immune to explosions?
Good for the first few waves. Once you get flamethrower w/upgrades, just repetitive. No endgame at all, and doesn't get harder fast enough for a surviorman challenge.
Don't mind natey- just look at his "Game" and adjust your opinion of him accordingly.
Include an inventory system, a combat system, and a few fights as the next step.