I have that same problem. Either there is another way to transition, or the author never implemented it and we have to select the next level manually.

Yeah I hate this ♥♥♥♥ with a passion and its the only uncontrollable flaw of the mode. No idea if the other hl episodes are like this or if a map fix (level transition trigger) is the issue. If you're in-game with another person and want to prevent disconnecting you can use the "changelevel next_map_here" command in the dev console.

Worse part is that the Lambda gamemode actually makes that load work... except that when you backtrack, your vehicle disappears and you have to hoof it to a checkpoint near the beginning of the map to regain your vehicle.

So, both co-op oriented Half-Life 2 gamemodes have problems with that particular bit of mandatory backtracking in the game.

this game mode doesnt support the episodes and lambda is broken citadel levels dont tranisition..........