Java game requiring Windows? Seriously, why is this even browser-based? If I could download the .exe then at least I could run it through Wine on my Mac...
What this game currently needs is a community; I suggest increasing the energy regeneration rate or including more things to do when your energy is depleted.
Keep everyone back, build cheap buildings to scout until the end of the map, snipe the boss with a spell to bait it, then kill the boss when it reaches your front step without having to go through all the crap in between.