The Leeghwater Project expansion adds to the base game Barrage:

• A new faction, the Netherlands, which uses the water management expertise of former Jan Leeghwater, adding more water to your dams.
• The Exterior Works mechanic, a set of very strong tiles that can be obtained in a new action space. You can do lots of actions with these tiles but be careful! In order to use the Exterior Works you must use the amount of concrete mixers and excavators needed instead of putting them on the construction wheel.
• The Personal Building. Each game will offer a combination of 5 building tiles, each with a different power that can be activated for your engineers.
• Two new top management officers created to increase Exterior Works and Personal Buildings.
• Three tiles of new advanced technology gifted to the construction of Personal Buildings.