At its core, the game is about designing airships and fighting with them. Ships are put together out of modules, and the layout of modules matters a great deal: everything on board is done by individual airsailors who need to run around, ferrying coal, ammunition, water and repair tools - and sometimes their fallen comrades.
You can command fleets of airships both against the computer and against other players across the Internet. (A match-making and ladder service is planned, but right now, you just enter your opponent's IP address). In addition, there is a single-player strategic mode, where you use your fleet to conquer city after city, unlocking new modules and bonuses with each of them.