I remembered someone tried their best to fully contain a similar first person shooter map with the exact aesthetics of the AWSD movement, arrow key head navigation, and left and mouse click system that remarks the handling of the gun in the map.
However, due to "bugs" and lots of funky triggering work, it did not work out well, especially when version 1.26a came out that time it seems like the user stop continuing it. I did however approved it sometime but alas the user contacted me to reject and delete it due to the complex system that came crashing down.
Last time I recall the toggle movement was slow and hard to navigate, and yes it can only work for Singles based from the last map I checked out.
I believe some users out there are preparing anew course of such FPS in the matter, it will be difficult to be sure. But it can be done.