Some people just love concept levels. With almost every sector of the map being cast in total darkness and a confusing progression (which can be partially revealed by pressing your F11 key an abusive amount of times) which in essence is an acrobatic teleporter maze with demons chomping on you from below, this is not exactly a Cacoward winner, but it does present itself as the perfect speed demo challenge. Yes, this time is very beatable. =P
CATWALKS.WAD is not available on doomworld.com/idgames/ or DSDA right now but watch this space! The level can however be found on the shovelware disc under the name, “Doom I/II Collection”, although I’m not suggesting you rush out and buy the thing – all the more choice picks CAN be found on the idgames archive.
edit: Spoke too soon – this level is known, and resides on idgames in a .zip called DMCATW! Watch this demo to see a trick variant of the same route, courtesy of TheGreenHerring.