You can't really call this a gameplay trailer.. the only thing that would make it more on rails, is if it acctully HAD rails... oh wait... It kinda feels like one of those hollywood rides based on movies. There was a similar trailer for Bioshock when it was first announced.
That said.. I do like bioshock, sure it had problems, but it was by no means a bad game, and I like the change of setting and style. So I am looking forward to the finished game.