I haven't treid your game yet (already have too many games to play which results in to litle time do do any programming) but based from the screenshots it looks quite good.

As for promotion I belive the easiest way would be to record some gameplay videos and post them on youtube. Another approach might be seding a few copies to varios gaming magazines and sites so that they can review your game. If you do decide to do this I suggest that you first send your game to some smaller probably local gaming comunity since poor review can be quite bad for promotion. ANd if you might get poor review you will atlest know what you need to improve.
And only if you see that they have given you good enough reviews you go and send copies of your game to bigger and more known gaming sites and magazines.
Actually I think that gaming sites might be best way of promoting your game if it is good enough to not get poor reviews as it would usually cost you just a few free copies that you give away to theese sites so they can test your game. And getting good reviews at theese sites can convince quite a lot of pepole in actually buying your game.