In E1L3 you can go to the right side of the yellow key door, if you kick it and press use it will open... Perhaps this is a leftover from this version. It also works in a few other levels (Rabid Transit on the Blue Key area).
You could open doors partially with the RPG in LameDuke too.
Edit: Sorry, I missed Zykov Eddy's post somehow

Erm... well... I at least confirmed this happened! Or... Some other excuse.
Ah, well, the plasma balls used to behave a bit like that in LameDuke though, as in, they would stick to enemies that were nowhere near the shot that was fired. In that bottom-most screenshot again, it looks like there may be a sloped sector towards the right.