For flimsy flesh beings such as ourselves, fighting aliens is rarely a good idea. For instance, Alec hasn't posted in ages because he attempted to single-handedly stave off an invasion and nearly died but then had to postpone to go help raise his new baby. But thanks to XCOM: Enemy Within, I realize that the solution to our easily fried human organs and tendency to give birth at the most inopportune moments was obvious all along. We just need to replace Alec (and all other would-be extraterrestrial terrorizers) with a really big robot. No, not that one. Mechs, silly. See them punch sectoids over waterfalls after the break.
See? Right over that waterfall! Did that move make any sort of tactical sense given that sectoids have all the fortitude of a bag of rotten peaches? Nope. But it sure did look cool.
More importantly, both mechs and gene-modded soldiers are extremely useful in the right situations. Mechs are natural tanks given that a) they have tremendous armor and b) are literally walking tanks. Gene mods, meanwhile, offer all sorts of handy abilities via new progression trees, including but not limited to defense against mind control and leaps that have the grotesque, terrifying dark future side effect of making trampolines not as fun anymore.
I got to play a little of Enemy Within last week, and the net effect of these new units was that aggressive strategies felt much more effective and satisfying. I usually turtle so hard that people want to turn me into soup, but mechs' ability to essentially function as mobile cover and a nice helping of active camouflage for weaker units made me feel like I was better able to control the battlefield. However, to balance that out, aliens have mechs too, and I nearly ingested my Adam's apple every time a sectoid gave one a near-impregnable shield via mind merge. The short version? It wasn't necessarily better or worse than the way I usually play XCOM, but it was certainly different.
Personally, I really enjoyed it. Not quite as much terror and uncertainty as Enemy Unknown, but more potential for strategic variation. Enemy Within will be out in November. Given, however, that we are, er, us, expect a whole, whole lot more about it before that.