I'll start tackling my list of games with Chain Reaction 3.0. To be honest, I read those rules some time ago but at the time, I thought they were more complex than I'd like. However, as the reaction system worked so well in Qwik, I ended up getting All Things Zombie on a whim and then I thought that learning the core system before trying that game could be a good idea. [A more rational approach would have been to try Chain Reaction before buying All Things Zombie...]
Before moving to the gameplay report, here's a short review of the book -- I don't feel it's necessary to elaborate much since anyone interested may simply download it from the Two Hour Wargames site.
Presentation: the book uses a two-column layout and is mostly black and white except for the images of the covers of other Two Hour Wargames titles that are spread throughout. The tables (an important part of this game) are very readable.
Writing: the writing style is a little more concise than I would like; in my opinion, it's better to be verbose and make things absolutely clear than having people guessing. On the other hand, I must admit that pretty much all of my doubts were solved by the text, even if it took me a second or third scan through the book.
Contents: the author explains tha this is a "lite" version of the games he produces and as such, it is meant to introduce players to the rules. That said, the book contains an impressive amount of material. There are forces lists for military vs. insurgents and police vs. gangs engagements. Rules for movement, ranged combat (including grenades), close combat, vehicles and buildings are presented, as well as the reaction system, which is the core of this game.
Solo-friendliness: the games from Two Hour Wargames are famous for being solo-playable and that's part of what drew my interest in the first place. The reaction system seems to make it easier to have an autonomous opposing force. The Chain Reaction 3.0 book includes a scenario called "Patrol" that can be played solo.
For this playtest I used the Patrol scenario from the book, with a 5-man squad looking for insurgents. Setup took about 20 minutes, including rolling dice for the terrain, arranging the results in a reasonable pattern, drawing the (rather crude) map in MapTool, and rolling for my squad and starting PEFs (possible enemy forces). The result is shown below, with the red markers indicating the position of the PEFs (slightly enlarged).
I won the first activation. Right away my squad moved to the sector to the left, without getting line of sight to any PEF (the one at the center of the map is within rough terrain which conceals them from outside.) During the enemy's activation, most PEFs didn't move but two of them approached my patrol.
The enemy won activation on the second turn with a roll of 6 -- resulting in no available forces to activate... so I moved my squad further to the right, revealing the PEF at the bottom-left sector, which turned out to be a false alarm.
In the third turn the enemy won the activation with a roll of 3, thus being able to move most PEFs. One of them entered line of sight of my squad, revealing itself as two soldiers. This triggered an In Sight reaction for four soldiers from my squad, with all of them passing 2d6. My squad leader fired first, allocating two shots against the enemy's group leader and one against the other soldier, resulting in three hits. The damage rolls resulted in the enemy group leader Obviously Dead and the other soldier Out of the Fight.
I won the activation in the fourth turn. Moving north, I got in line of sight of another PEF that turned out to be a six-man squad with the enemy commander! They got an In Sight test, with the commander passing 2d6 and the others passing 1d6. The commander fired at my squad's leader getting a Knock Down and an Obviously Dead result. Rolling his Star Power, both results were reduced to No Damage, but two Star Power dice were lost. The attacks triggered a Received Fire reaction on my squad, with all passing 2d6. Four of them ducked back, having no line of sight to the enemy. The squad leader, however, fired back, targeting three enemy soldiers and taking one down. This, in turn, prompted a Man Down reaction from the enemy group, who passed 1d6 and ducked back. At this point, I moved my squad leader behind cover with his remaining movement. The enemy activated, starting with the group that was just revealed. They passed 2d6 on the NP movement table but since my squad had ducked back and was concealed, there was nothing to do, so they just remained concealed too. Another PEF resolved into a False Alarm and two others moved still unseen.
In the fifth turn the enemy won again with a roll of 6. I got a roll of 5, being able to move my squad, who advanced a little towards the top of the map, while keeping out of sight of the enemy squad. The board, at this point, looked like this (the sectors marked "OK" are the ones already covered by the patrol):
This playtest took a little more than three hours to complete, but then again, it involved constantly checking the book to make sure I was following the rules and taking notes to build this report.
Chain Reaction 3.0 is a complete game in itself and the reaction system makes it work well for solo games. The NP Force Movement Table provided in the Patrol scenario might also be a good starting point for the creation of automatic behaviors for other solo scenarios. In the end, I think it's an innovative game system, well suited to play scenarios (rather than simple pick-up games) and the emergent behaviors from the reaction system are really cool.
I'd advise anyone new to the system to read the book once, then stage a simple confrontation, say three figures on each side of a building, then take a second look at the text. Many of my doubts happened at the fourth turn of my playtest when the "chain reactions" did really start happening and I think that playing some basic firefights before trying a full scenario would have helped.
[Update: after checking the Two Hour Wargames discussion group, I found that I was resolving reactions too early. For instance, you should first resolve all ranged fire from a group, then roll the Received Fire or other reactions for the targeted group. If there are multiple reactions, for instance Received Fire and Man Down, you should roll all of them and pick the worst result. So I'd add to my advice: check the discussion group for clarifications.]