Message Types:
- chat (sends like a regular chat message)
- overlay (displays centered on the client, above the action bar)

Message Schedules:
- on_first_join (sent when a player joins a level for the first time
- on_join_level (sends every time a player joins a level)
- on_death (sent every time the player dies)
- on_respawn (sent every time the player respawns)