This is extremly hard if not impossible to complete on the hard level. the only bug I know of is that you can't save it on the hardest level.
Credits:
Jamie Rothman for playtesting.
Base:
New level from scratch
Build time:
Editor(s) used:
DEU v.521gc, edmap 1.21b
Bugs:
If there are too many arch-viles near monsters, some of the monsters might be in clipping mode. To kill them you must fire rocket at wall near monster.