I'ved enjoyed the few sessions I've had of playing this with my kids. It manages to give a nice approximation of world war I dog-fighting with very simple materials and rules. You pick a playing surface (table top, rug, whatever), each start with an airplane card or two at an edge, and the choose maneuver cards for the next three moves. Once both players have planned their moves, they reveal them, moving their planes across the play area using the arrows draw on the maneuver cards. If the planes get in range of each other, they can shoot, and the target player must draw cards from a damage deck. A simple mechanism that works well for a friendly game. I like just flying the cards around the tabletop without having any game board. It feels very free form.
Different planes use different maneuver decks and different damage decks, which are supposed to accurately reflect the capabilities of the real planes. So, for example, the two seated planes that are the stars of "Watch you Back" all use the "H" maneuver deck, which does not allow them to do Immelman turns (which in the game works basically like a turn on a dime), so the single seaters have an advantage in maneuverability, which can almost make them evenly matched.
"Watch Your Back" comes with the "B" damage deck and with the "E", "F", "G" and "H" maneuver decks. There are a couple problems with that. First, a few of the planes that come with the game use the "A" damage deck, which does not come with the game. (You can get it with "Burning Drachens" or "Famous Aces".) This is not really too bad, because you can more or less fake a "A" deck by having people draw two cards from the "B" deck, since the A deck does about twice the damage as the "B" deck.
The second problem is that, while the damage deck is shared between all players, each plane must have it's own maneuver deck. Since you only get one of each of the four maneuver deck, that means you can't have two planes with the "H" deck fight against each other, unless you get a second "H" deck which you can only do by buying a second copy of "Watch Your Back". Though I suppose a few minutes with a photocopier would be an viable alternative.
So if you have just this one game, there are limitations on the matchups that you can create, since you have to choose planes who use different maneuver decks, and that makes it a little hard to set up balanced games. There may be a certain realism to that, but it can be a bit trying from a game play point of view.
I probably will buy some more sets, since this is rather fun, but I think it's worth knowing what you are getting into when you buy this.