Designer's Notes: (From the 2010 rules update.)
"I can't even remember what inspired me to throw this Risk variant together a little over twelve years ago (uh - boredom?) It was posted on my old website for the rec.games.board
crowd to try out and I guess a few people actually gave it a spin before I took the website down."
"In response to a recent [May 2010] request from a BGG user looking for the variant, I was able to locate the original ugly 'old-school' HTML file that I posted back in 1999. I reformatted the HTML file to create this PDF edition, cleaning up the wording in several places, but unfortunately retaining the awkward numbering. The gameplay itself remains unchanged from the original prototype 0.1 version."
"I look forward to hearing about your attempts to conquer the Earth!"
Additional comments from the designer:
As you will gather from reading the rules, Alien Invasion is not won by using the same strategies as you would use in Risk - in other words, the variant was not designed to be some sort of solitaire Risk simulator.
Indeed, Alien Invasion might be more accurately described as "a solitaire game played using Risk components" rather than a "Risk variant", even though some basic elements of the Risk rules are retained. In retrospect, I think one of the ideas I had in mind when I was working on the design was to come up with a new game that could be played using the components of a commonly available game. While I did some playtesting of the rules myself, I don't believe I received any outside input regarding the variant after it was released "into the wild" (with little fanfare) back in '98 or '99. I'll be interested to see what flaws are flushed out by the BGG crew!
Alien Invasion was influenced by my experience with more complex solitaire games such as B-17: Queen of the Skies, Mosby's Raiders and Ambush!, as well as a number of solo sci-fi games. Although nowhere near as complex (or meritorious!) as such titles, general concepts that I found enjoyable in those sorts of games worked their way into Alien Invasion. These influences also explain why the rulebook is longer than the Risk rules - that's just the gaming background I come from. Prepare for possible culture shock if you are a "new age" gamer!
The game system you are "playing against" in Alien Invasion relies heavily on elements intended to create uncertainty and increasing difficulty. These elements of the game system are "explained" with some thin background paragraphs. This is where the player should step in and apply some writer's embellishment in keeping with the broad 50's sci-fi theme -- mentally creating a narrative of what is unfolding as the game deals out surprises stemming from the fog of war, inter-service rivalries, or the plain-old cunning strategy and resourcefulness of the Earthlings (and you didn't think they had it in them, at least not until it was too late...)
I think players who approach the game in such a manner will get the most enjoyment out of Alien Invasion, but I also look forward to hearing back from the number crunchers regarding what they think of the game.