Your internet connection may make it difficult for you to fully enjoy the game.
The main part of the game is the Online Kingdom where you build up your city, battle other players and go on quests. A lot of the Online Kingdom can essentially be played singleplayer but PvP battles are a big part of it and more online content will be added over time. To reduce the chances of PvP battles going Out of Sync, the game updates each time you start it.
There is no LAN support or content and this isn't likely to be included any time soon.
There is singleplayer content in the form of Skirmish modes Lay Siege and Castle Defense where you attack or defend one of 12 castles/cities, as well as a conquest mode called Kingdom Wars with 3 campaigns and the possibility of starting with any one of the 12 major cities.
While we would like as many people to buy the game as possible, you need to be sure this is the right game for you.