After dropping down the fans in Sintek Chemical Plant I seem to get stuck "in" the flor. I can't move much, though jumping sometimes gets me unstuck only to get restuck when i land, and the whole screen is bouncing up and down very rapidly.

The problem persists all over the lower level even if I use the noclip cheat to move past the fan well. I sometimes take damage from being in the floor as well.
There is a similar issue in one of the fan ducts on the upper level. I can move, but only very, very slowly. No screen bobbing there though.

This is the 2.0.9 download, game version 1.11 as far as I can tell. Does anyone know how to fix this?

It seems to have been related to the elevator somehow. After triggering it, the rest of the level mostly worked.

yeah, this was an issue even before the gog version.

If you're desperate you can open the command console using the ~ key and enter noclip so you can move around on the lower levels, alternatively, you can skip the level entirely by entering "map whouse1" to load the following level.