/vr/ - Retro Games

>>1868369
>Is there something that is more like Zan in regards to multiplayer but doesn't use real 3D (GL)?
"vid_renderer 0" or select Software from the startup menu.

>What are some good maps/modes/mods for coop?
Try the classic AV, Memento Mori 1/2, Plutonia 2/Revisited, Jenesis (don't know if multi compat but it's a nice mapset), Scythe 1 and 2, Hell Revealed 1 and 2, etc

>Is there a way to make coop more challenging? Being able to die and respawn immediately and repeatedly without losing progress seems too easy and ruins the fun, challenge, and adventure.

Use Survival mode and set how many lives you want each player to have. I assume you're familiar with how to set up dmflags to customize whether things like health and ammo respawn and disable jumping/crouching/etc

As for savegames, unfortunately, there isn't a way to use them online, which is pretty much the only thing I like ZDoom online for.