This looks like it is the next Industry Giant gem, but more accessible. The thing I most love that you have ( either in the works or currently in the game ) is the proceedurally generated world that will grow as your expansion grows to the edges of the map. To me the most frustrating thing in city or transport games in the map limitation. You always have to stop somewhere. This will be the first game in this genre, as far as I know, that the build area will grow as long as you want to play the map. That is awesome!.
I do also want to say I love the concept of having airships in the game. Is there any chance at all that you design in the ability to research or produce steampunk products ? I think that would be very cool. Not required for a great game, but it would be amazingly cool.
Anyway, don't you dare stop developing this game! This is the next Space Engineers. Keep the community informed on a frequent basis now and especially when you get to Steam and your game will gain insane momentum, I bet. Slow and steady can turn into a rocket, just hang in there. $20 is teetering at the edge for the price of a brand new early access game, but don't let the weenies talk you out of it. You have the quality right now to get it. Game play is more important than graphics. Factorio sold for a long time before it ever went to Steam. It looks a lot worse than what you have ( not saying what you have is bad looking lol ) . Anyway I will get it later today, but I had to write this now. Keep your chin up when people get nasty. You are doing GREAT!.