NavyField is a 2D strategy MMO. Room based combat where rooms go upto 64 players in a team based setting. Players are represented by naval ships of different classes(Destroyers, Light Cruisers, Heavy Cruisers etc) and combat is sort of Gunbound, where you line your guns and set an angle to fire at.
You have to keep a crew which specializes in aspects of the ship operations like Repairs, Gunners, Bridge Officer etc.
The game is F2P with a premium option for extra EXP and there are premium ships to purchase. The game is totally playable without premium as well.