By the end of May, Ed from Two Hour Wargames (THW) announced that he was about to release an update for the free Chain Reaction and Swordplay systems. Today Chain Reaction 3.1 Final Version has been released. This is the "introductory" game for people interested in THW products and also a very flexible toolbox that allows solo (or co-op) play of a variety of skirmish scenarios.
So, what has changed? For starters, the new book is even better organized than the previous one. The many examples and the "Stop!" boxes will probably be very helpful for newcomers.
The rules also saw some cleaning up and streamlining. Many different reactions have been grouped up into the Crisis and Recover tests. One could argue that the reaction tables still have conditional text for some specific situations. Still, this move makes the learning and look-up of reactions simpler. Oddly, the simple campaign present in the previous version has been removed.
Lastly, there is some blending of old and new ideas, as could be expected as the game systems evolve. For instance, the "hunker down" status has been added back. This, along with the "duck back" status can model different levels of suppression. The "in sight" test also looks like a mix of those found in 5150 Star Army (and older titles) and the one introduced in Chain Reaction Final Version (and also present in After the Horsemen, 5150 New Beginnings and Urban Renewal.)
Overall, I would expect this new version to be easier to learn and faster to play. I am thinking of adopting the new "in sight" rules for Star Army, and maybe even other titles that I own.