Mouse + keyboard: click to capture the mouse, W A S D to walk, Space to jump, hold C to crouch, hold Shift to run. V switches to flying (F/Space up, Q/C down) and back. G drops a physics box. Esc releases the mouse.
Controller: press any button first (browsers hide controllers until then). Left stick moves, right stick looks, A jumps, B crouches, click the left stick to run, D-Pad Up flies (triggers up/down), Right Bumper drops a box.
Animations: press N (controller: Y) to switch the characters to their next animation.
Slabs: press L (controller: D-Pad Down) to unload the extra Slabs and load them again.
These are the default controls. Change them in game/config/input.yaml. Logs: press F12 and open the Console tab.