Well...
I was reluctant to write a review at first; the main reason was the difficulty of writing a useful review, instead of just praising the amazing work you have done. Then I thought, what the hell, an artist needs the good vibe, too.
First of all, my review will be biased, since I consider the whole "Mastermind" Series (if I can call it that) one of the best examples of good humour, not only in flash, but in art generally. Therefore, it can only follow that the atmosphere of Mastermind: WC was wonderful, balancing between the hilarious, disturbing, insane and the dark with unmatched skill.
However, this is not what really surprized me; it was to be expected. What really made me say "Ooohh come on! Why does this keep getting better and better? I also need to work, dammit!" was the gameplay. I happen to be a fan of strategy games, both flash and commercial ones, and rarely see innovative ideas in the field (especially in flash). Well, I believe that your approach had this difference needed to make this game stand out, instead of just being "a good clone of game X, with a different theme". Moreover, the whole gameplay really puts the player in the position of the Mastermind, feeling and acting as a deranged, hate-driven criminal with the sole purpose of destroying Earth. The humorous elements, although ABSOLUTELY hilarious, did not negatively interefere with the (optically and otherwise) dark theme of the game.
The mission/meeting cutscenes were another addition that took the game from "pretty good" to "freakin' excellent". I have always thought that a strategy game should include such cutcsenes. In fact, some do, but in a very boring, repetitive way. By changing the dialogues and creating many variations depending in the mission and the supervisor, you kept me watching them over and over again (the humorous elements also helped towards this end).
I really hope to see more such games from you, offering other innovative ways to exploit the genre of strategy games. This attempt was indeed the work of a mastermind...