I think it's essentially Song of Blades and Heroes - so individually based skirmish rather than rank and flank.
The core activation mechanic is rolling between one and three dice to determine the number of actions. A success is equal to or higher than the character's quality score (Q), so the lower the Q, the better (2 is best). Rolling two failures are once ends your turn. So if you rolled 1, 2 and 6 for a Q3 character, he or she would get one action and then play would pass to the opponent. The big conceptual thing is the risk/reward balance - aim for more actions at the risk of ending your turn or play it safe by only rolling one die for each character?
An activated character can move, shoot or attack with an action (generally only once per turn for the latter two, although two actions can be combined to give an 'aimed shot' or a 'power blow').
Combat is like DBA - an opposed d6 roll with modifiers, chiefly each character's combat stat (C). The highest total wins; a doubling of the opponent's total is a kill.
That's about it - the action economy and 'how many dice' decision are at the heart of the game. It's a great way to teach small children simple addition and - eventually - simple probabilities. For very small kids, it's probably best to give them a force made of a few powerful characters with good (i.e. low) Q scores so that they always roll three dice and only 1s are failures. Kids don't need to understand the probabilities initially - there's the excitement of rolling dice and hoping to avoid 1s (or 1s and 2s or whatever).
The SOBH engine is really good, and the action tends to be quite cinematic - knockdowns, pushbacks and so on.