This game saves your progress. If your progress is not saved:
* Make sure your browser allows cookies.
* Make sure your browser doesn’t delete cookies on exit.
* Make sure you are not browsing in private / incognito mode.
* If you are using any software that deletes cookies (like CCleaner), disable that feature.
* Kill all the bad guys.
* Click & hold to shoot.
* 1-7: Cycles through arsenal.
* Tab: toggles between traps and weapons.
* Space: Send incoming wave early.
* P: Pause.