Hey man,
I'm liking the tone you are going for here however I would like to offer some constructive criticism if I may.
Firstly you could take a look at your layers, most themes should have a foreground midground and background...the foreground being what you want the listener to be attached to, midground should support and enforce the foreground and then the background should fill the space and allow the front two to define the piece.
Secondly I couldnt find anything in the track that could be classed as a theme....i theme should normally have a melodic or rhythmic phrase that you can catch on too...kind of like a hook in a pop song, that one thing that you could play by its self and you would instantly recognize. The way this track is at the moment it would be easy for you to introduce a 'hook' onto it.
(listen to the Superman theme for an example of a melodic theme)
(listen to battlefield 1942 theme for an example of a rhythmic theme)
Hope that helps.
Dan