AirBuccaneers is different than your usual first person shooter fare. That scores it bonus points in my book for innovation alone. An interesting idea alone doesn't make a good game but AirBuccaneers is executed, not flawlessly mind you, but well enough to make for a very enjoyable gaming experience. It has come a long way since it started as an Unreal Tournament mod in 2003.
Before I go into the details I have to tell you my main gripe I have with this game, it will most likely be a dealbreaker if you're considering a purchase. It's multiplayer only and the community is pretty much dead, if you login today you will most likely find all servers empty. A problem far too many old, indie or non-mainstream multiplayer games face.
Try it with a group of friends or join a Steam group that is dedicated to organizing AirBuccaneers sessions.
AirBuccaneers pitches two teams of air-balloon crews, "Vikings" and "Buccaneers", against each other in exciting ship-on-ship battles. Each player assumes a role of his or her choice, a role that can be switched fluently during the game. Pilot a ballon and order yor crew around as a helmsman, man a cannon as cannoneer, repair damage done to your balloon, engage in ranged or melee combat (yes, enemy ships can be grapple-hooked onto and boarded), set up floating mines or support a teammate (for example one of the cannoneers to allow him to fire at a faster rate).
Cannons are far from accurate, so skill in this regard doesn't matter as much as in many other first person action games and if you consider your aim still not good enough that's not a problem either: Just assume another role that suits you better.
As you may already have guessed, teamwork is everything. The fact that you're totally dependent on your fellow crew members simply doesn't allow to play as a lone wolf and leads to almost organically developing teamwork very fast.
The only persistent element of the game are the skill trees, a different one for each role. Which path you take is not entirely up to you but progression is assigned automatically depending on your actions during matches. To me, this feature feels superfluous, I never had the feeling that it influences the outcome of a match at all. Maybe that's because every perk is evened out with a debuff and that's probably better than having new players start at a disadvantage.
Instead, the game allows for imbalance in another way: Since players can switch teams any time they want in absence of an autobalance system it leaves it entirely in the hands of the participants to form evenly sized teams.
In conlusion, I'd recommend AirBuccaneers to everyone if it weren't for the lack of a player base. It certainly is a game that deserves to be revived, I still hope that it will at some point but wouldn't hold my breath.