I played a(n even more) simplified version of HG Wells' Little Wars with my son (age 6) this weekend. I played an 18 figure all-infantry Army Red against his combined Army Dark Blue forces of 24 infantry and 8 cavalry. Each side was equipped with a Playmobil cannon. Victory would go to the first side to get three figures to the opposite bound of the playing field. Melee was decided by simply throwing a die each with loser tipping over a figure – in the event of a tie both figs were knocked over. Terrain was board books stacked upon eachother and some Lincoln log structures. We obeyed Wells' rule of "guns first": that is, you fired your three shots with you cannon at the top of your turn, then did all your movement, then resolved any melee. All movement was 12 inches.
He won rather convincingly but highlights (which placed us firmly in the land of play) included my hitting a cavalry figure, and then having it fall over and knock his companion over, and so forth twice more, like a row of dominos, killing four in one shot! The other trick shot was firing a dart through the doorway of the Lincoln log structure and back out the opposite side to knock over two Army Dark Blue troopers who thought themselves protected.