@Knulp14: Probably the Adobe Flash local storage is too small. Right click on the game, click "Settings" and slide the slider to "unlimited". That should do it. I lost my saves due to a new FLash version which reset the storage >.<
Not a bad concept. I am baffled by the "saving", though. Somehow I get a save game with lvl4 character, -46.5% xp, and no newer save seems to appear. Exiting to the menu does not replace the old "save".
The spawners' bug is annoying but doable, makes it more challenging.