well i dont know anything about this game, but the x-series was always an open world game (sandbox genre, first person view). you can do pretty much everthing you want. shoot, trade, tune your ship, buy new ships, explore etc. but i spent most of the time building factories and mines.
and yea its a bit like freelancer but a lot bigger (huge universe, nice economy system). you can change the environment buy building stations, factories and mines
http://en.wikipedia.org/wiki/X3:_Terran_Conflict