Dobandon Have only been able to replicate these bugs regularly in Mozilla Firefox, seems to work fine in chrome. Most of the incidences of falling through happened here: Floor1
Often times if jumping off I'd either go right through everything, or end up in the pipe below: Floor2
I really only encounter problems with the very last lift: Lift
Sometimes it works no problem, other times it doesn't let me go up unless I am pushing both up and right simultaneously. It could be because how narrow it is compared to the others.
Hope this helps :)