Stuck in Commander Keen 5

[Guest]

Hey folks.

I just got all of the Commander Keen games out of storage and have had a blast playing them. I've made my way through to Keen 5, but I have gotten stuck on Level 2 "The Security Center". Apparently I have to drop down two holes in the floor to progress, but nothing, save the No-Clip cheat, allows me to fall through those holes.

I'd rather finish the game without cheating, so does anyone know how to fall through the holes in Keen 5?

Many thanks.

[486 player]

Down+jump.