Carriage reminded me of an awesome micro-intensive RTS game, Ground Control, which is available on FilePlanet as a free download. It might be the 'free version' but it still has lots of levels, and I don't really see what the diffrence is between the free and real game. Try it today, and get your RTS skillz in order! Ground Control Free Download!
As far as I know it's completely same game as the retail one. It's been free for ages. A word of warning though, the sounds start looping in briefings at times and won't stop until the briefing is over.
Yeah I noticed that, but it's not that bad. The only thing I found hard in missions was protecting things while moving in a convoy; something either went to far ahead or lagged behind and died.