Some modest but promising progress:

What you see here is two instances of C-Dogs SDL, connected over localhost. One is sending move commands to the other. I haven’t added direction in yet, hence the hovering.

The hard part about adding networked multiplayer to an older game like C-Dogs is its architecture: the whole thing must be partitioned into client and server portions, with events connecting the two. That’s well under way, but connecting everything up is fiddly and feels like transplant surgery. Fingers crossed, the next version of C-Dogs SDL might have networked multiplayer!