I’m stuck at delta lads level four, and have given up.... 
Hm, it's not a great game indeed, looks good, sounds better, it just Doom..
/OT
Anyway, I is that the level where you can't get back the way you came and the walkway collapses partly on your way back ? And if you fall/jump down the walkway you can use a ladder to get back but the "only" way out is to high for you to jump ? If this makes sense then look for a wall that looks like flesh. It's a tunnel...
Can't check it anymore, gave the game back to the original owner..
