We used a set rules called Land of the Free. Let me start out be saying that I'm not really a fan of what I've seen in these rules. Maybe we made some fundamental mistakes but it seems like units can do a lot of things in a turn, like shoot three times. Now I'll concede that I had really crappy die rolling (I think I only passed morale checks for the artillery all game) and that definitely played a role in how I view these rules. I do think a game should be able to compactly summarize itself into 2-4 quick reference pages. For some reason, these rules use 6 pages and there's no reason they shouldn't have been on 4.
Let me explain what happened prior to the picture. On the left, not much happened all game. I advanced three units to the fence and I was content to leave them there to protect my left and the guns. You are seeing it beginning to crumble because I could not make any morale rolls and my units had to retreat.
On my right, I sent an entire brigade of a large unit, a unit of skirmishers, a medium unit, and a small militia unit vs one large unit (plus one 1/2 unit that could fire out of the house). My skirmisher went first and had no effect but they were driven back. Next turn, I advanced my medium unit and my large unit. The British responded with delayed fire and naturally drove my medium unit back before I could fire myself (reasonable enough, I suppose). My large unit fired twice with little effect, mostly because of crappy die rolls. The British won the initiative and fired three times on my large unit. Each fire was 8 dice and hit on a 5-6. That's basically 2-3 hits per firing and every 4 hits drops the unit's morale by 1. Combine that firepower with my miserable die rolling for hits and morale and I didn't achieve anything. It wasn't until I managed to sneak a small unit of militia onto the road that I managed to get enough hits on the British unit to drop it a level of morale.
Shortly after this photo, my two American units routed leaving only the militia behind. It was at that point, we called the game.
To me, these rules seem too fiddly for playing a lot of units but they also seem to need a lot of units to smooth out the swings in luck. But I'd be willing to give them another go just to see if knowing how they work would improve how they play.
