This has been a slow gaming week for me rescued only by an excellent little Flash game called "Creeper World" (yes I do get some kind of worthless reward points if you use that link). It is an RTS game where you must fend-off a never ending tide of purple ooze using lasers and mortars. The rate at which you can build new structures and the rate at which you can fire your weapons is limited by available energy which in turn is linked to the territory you control so there is quite a nice little bit of resource management and territory control going on. A further refinement is that energy isn't instantly available where you need it but must travel in packets from your central hub along a network of interconnected nodes that you construct. This simple mechanic keeps you on your toes throughout the game because a momentary lapse of concentration could allow the creeper to sever a branch of your network isolating areas from their vital energy supply. (Gameplay hint: Use relays liberally to reinforce your energy network). My biggest complaint about the game is that later levels take too long to complete without the option of saving your progress. I took me more than an hour each to finish the last few levels which is more than you expect to have to put into a flash game. There is an extended version available to buy and I am still considering whether to get it.
Thanks to Zubon from Kill Ten Rats for recommending the game.