Prelude is a very old game, with an interesting concept and just a few key things missing from its execution. With a bit of care and attention, it could be something special, and I really want to come back to it some day.
Controls are now bindable in game, see the "Options" menu.
The current build contains a testing "construction" feature.
Select which tile to construct with L and place them by clicking in the game world.
Ancient design doc here.
Old version here - with more zombies attacking.v0.18