Party Modes
Alongside the competitive modes (X01, Cricket/Tactics) and the Practice modes, the game-mode picker has a Party section — casual, multiplayer-focused modes. Selecting any of these still goes through the same lobby flow — choose a scoring method, pick your board, and start.
See Practice Modes for the full mode picker screenshot showing all three sections.
No Bot opponent
Like the Practice modes, none of the Party modes support playing against the built-in Bot — these are multiplayer-only, whether that's a local guest on the same board or another player online. Killer in particular needs at least two other players to be worth playing, so its screenshots (still pending) will show a 3-player game rather than 1v1.