When attempting to play the game tonight I ran in to a little bug. When I was in the middle of telling a plane builder to build a few things it got stuck. I couldn't place anymore items and I couldn't select any other units. I was pretty much just stuck looking at a transparent wall piece that I could not place down and it just followed my mouse. For the next 5 minutes as I tried everything I could think of to get it unstuck but nothing worked. The game itself wasn't stuck, it was only my ability to interact with the game, besides being able to move around that planet and other planets. I ended up just having to close the game.
It may have been a server issue at the time which caused this issue, although i'm not 100% sure. Since the game runs from a server at this point in time issues like this aren't uncommon. So i'm not too sure if this is the case but this is my take on the issue. Also are you running the stable or PTE builds? info might help others to work out what issue you had if i'm wrong.
I was playing only against the AI 2 vs 2. I have the newest steam build 69564. This has happen to me before in a older build also against the AI but last time I was able to get out of it some how after about 2 minutes of being stuck. I have no idea how I was able to get out of it last time but I tried everything I could think of and was unable to this time. Edit: Come to think about it I think it was a plane builder guy last time also but I don't remember if he was a lvl 1 or 2. This time he was a lvl 1 builder. I should probably clarify that I don't know the proper names for these units. When I say plane builder I don't mean plane factory but you probably understood that after I said I got stuck with the wall piece.
quitting the game and reconnecting will allow you to finish the game. it's a bug uber are working on fixing : http://pa.lennardf1989.com/Tracker/index.php?do=details&task_id=3747