I have managed to put my hands on the Risk rulebooks from 1980, 1993, 2003, 2008, and 2011. As far as game play, they are almost identical with only minor tweaks to troop reinforcements (how many you get per turn) and starting number of troops.
In '93 they introduced missions, and each proceeding set "improved" the mechanics to some degree. The '08 set significantly retooled of the mission system, plus they added cities and capitols. They also changed the official way to determine starting territories.
One element I thought strange was that the most significant changes between all 5 sets of rules are in the 2-player rules variant ('08 doesn’t even cover it). Within that sub-section, the biggest differences are whether or not to include neutral armies, and whether or not the allies are passive or aggressive.
I recently picked up the 2008 set because it had cities and capitols (unique to the set). But I will be playing this mostly with my son, and it didn’t cover how to play a 2-player game, I looked at how the other sets handled it. My old '78 set had 2-player rules (without allies), the ’93 set added 1 neutral ally, and the ’11 set is the same as ‘93. However, the '03 rules include a very extensive set of instructions for including multiple aggressive neutrals/allies.
After reading through all these editions, I made up my own rules!! Essentially, I blended the '93 and '03 rules in the framework of an '08 game (cities, capitols and enhanced objectives/missions). I am really pleased with how it all turned out. This is a PDF of what I came up with.
As I mentioned in a previous post, I also started working on a custom map for Risk. I like it, but have decided to take a dramatic turn in direction. I will share my progress in a later post,
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