Tried co-op w/ my gf and the game kept choking and dropping to 0 fps, just like the topic's title says.

Both of us can run the game in 60+fps in singleplayer. Does this happen because of the delay between our computers?

Delay was 50-130m/s so i set the delay to 150 just in case. Tried dropping it to 130, upping it to 200 but nothing significant really happened.

/portalfx off also did not fix it

Other than this problem, good job on the mod!

If the connection is excessively choppy, the game will stall while there's nothing coming through.

You can assess the situation by holding Tab and watching whether the displayed ping for the player is periodically jumping into hundreds. Connection graph below it would also reflect the situation. There's also framerate displayed there, which should be convenient, since you mention that the game runs at 60+ fps but it is locked to 30fps unless changed with mods.

Sometimes it's Steam fault and restarting it fixes the problem. Sometimes it's the actual connection being odd.

LAN totally worked. I decided to plug our PCs to a spare modem I had lying around. Now we have 16 m/s constant ping. No more lag! :D

Thank you so much for making this mod and making the game even more enjoyable :)