They have one projector per wall panel, making for 4 projectors per sim. Left, front, right and top. Note in the pictures I grabbed there is a 0.32:1 ultra short throw on end and an Epson laser-LED hybrid projector mounted over it. The pictures don't reveal the mounting locations for the side panel projectors but they're most likely mounted back a ways long throw and at an angle. The angle corrected by pre-warping.
They could have done a bit better with their pre-warp alignment on the panels. Notice the terrain miss-alignment. Not a bad setup, but anyone with $3000 can replicate the visual system.