Hi there, I'd like to propose a new game mode idea: Constructor. This is a very rough idea, I didn't work out all the details so expect to have many holes in it.
What is it?
It is a building oriented game where two competing teams are battling to finish their own building first. The winner takes the money, the losers go home and wait for the next round. Each round features a different building, you could set if you want each successive building become more difficult to build, or just cycle buildings randomly. Each team can buy upgrades at a shop which can help them or screw with the other team. While building itself can be tough, teams also have to keep an eye on the other team, as they may have some nasty surprises up their sleeves.
How would it work out?
Teams:
Each team would have two classes: the foreman and the workers. The foremen are responsible for getting things done, they are the ones who can see the blueprint. He can't lay bricks, but he can reveal bits of the blueprint to the workers if needed. Workers are pretty much doing work. They lay bricks, or go on a sabotage mission on the other team's site.
Building:
The task is to build a building according to a blueprint, which is in the form of a stack of ghost bricks, much like what the new duplicator duplication looks like. As mentioned, foremen can see the big picture, his job is to coordinate the builders to lay bricks. The game would need some default buildings, but there should be a way of adding new buildings too to the repertoire.
Shop: There would be two kinds of items. The first category would be the building aids. They can make the workers go faster, give the ability to the foreman to show bits of the blueprint for a longer time or at more parts of the building, or improve on the brick laying speed. The second category is for gaining an unfair lead over your competition: you could buy different bombs for the sabotage missions, or other things.
Sabotage: Each team can select one worker to sneak in the other construction site and place a bomb. Placement of the bomb is important, the more bricks destroyed the better for the other team. If the saboteur is discovered, he can't plant the bomb. This probably works better with larger construction sites with more bricks and people around.
Difficulty: There would be many settings to make a game easy or tough. Things like setting a time limit, allowing saboteurs, changing the build cycle, turning on fall damage and limiting the number of respawns (yes, construction sites are dangerous).
Winning: The goal is to finish the building first. At any cost. If the time runs out, the game resets. If by some freak accident all the workers die (well, hospitalised permanently) the game resets.
I think this is pretty much what I have in my mind so far, I'm sure there are a lot of things which should be refined, but this should give you an idea about what the game would be like.