EPIC DEFENDER
Pure Win
Reasons:
I. - Concept; I mean, this is a truly original perspective for a defense game.
II. - Story; the simple fact that I'm the so-called "badass" monster that merely tries to defend its beloved treasure the so-called "heroes" are trying to "win" from us.
III. - Buildup; it's got a steady, well-balanced increase in both features and difficulty.
IV. - Music; not distracting, but intense and gives the game that true construction feel from RTS and rampage-action games.
V. - Impressive preloader and gamesafe-implementation; it's not aggressive at all, yet you keep peeking at the icon time after time.
Colors and contrast are a bit too hardcore for my LCD though, and it doesn't meet my gore/pr0n factor, but hey - can't stuff everything in a single defender, right? :P