Just to add to Vanoord's post; the collapse just after the 2nd abseil was (IIRC) about 10 years ago, and the route now deviates over this flooded chamber via zip wire:
πCroesor-Rhosydd-Through-Trip-13-01-2007-Image-002[linkphoto]Croesor-Rhosydd-Through-Trip-13-01-2007-Image-002[/linkphoto][/link]
It then used to cross a second flooded chamber over a funky ladder bridge:
πCroesor-Rhosydd-Through-Trip-13-01-2007-Image-003[linkphoto]Croesor-Rhosydd-Through-Trip-13-01-2007-Image-003[/linkphoto][/link]
But that's gone now, taken out by a block of ceiling landing on it. It's now a short boat trip. Or a swim ;)
It then joins the old route.
On the exit side, I'm not aware of significant changes at the Croesor end in the past couple of years, short of seeing one block of ceiling come down about 2 years back. But then I only did it for the first time in summer '06 so don't know much about that end of the trip before then.
my orders are to sit here and watch the world go by