these are very addictive but I'd like to see other monsters besides the cyberdemon doing the fighting

For a while it looks like a cartoon fight cloud with arms and legs poking out of it.

No enemies can ever focus on the pain elemental. It's part of the game's programming.

This shouldn't have been as close as it was - there is a limit to how many spawned Lost Souls can be on a map that is part of the game's programming. If this were not the case, we would have seen a lot more Lost Souls about.

Also, the Cyberdemon has a weakness to close-range sorts of stuff. It's AI makes it back up when something is close to it. This is unwise to exploit as a player, since it's about as likely to shoot you as it is to back up, but with this many lost souls about, that weakness becomes very noticeable.

It's possible to chainsaw the cyberdemon to death, because of this weakness. Though, if you manage it, we need to have a conversation about next weeks lottery numbers.