According to this wiki page:

Survival

• Intended to encourage cooperative play.
• When players die, they become ghosts.
• Ghosts can be revived by certain items.
• When all players die a timer starts. If nobody revives themselves before the timer is up, the world resets and all players start anew.

Endless

• Intended to be more relaxed and casual.
• When players die, they become ghosts.
• Ghosts can be revived by certain items, but also at the spawn portal.
• Even if everyone becomes ghosts, the world never resets.

Wilderness

• Intended to be more like other survival games.
• Players spawn in random locations.
• When players die they do not become ghosts.
• Dead players lose all their items and map information, and respawn at a new random location.

According to this wiki page:

Survival

• Intended to encourage cooperative play.
• When players die, they become ghosts.
• Ghosts cause the sanity of living players to drop if they are nearby.
• Ghosts can be revived by certain items.
• When all players die a timer starts. If nobody revives themselves before the timer is up, the world resets and all players start anew.

Endless

• Intended to be more relaxed and casual.
• When players die, they become ghosts.
• Ghosts have no effect on the sanity of living players.
• Ghosts can be revived by the same items as Survival, but also at the spawn portal.
• Even if everyone becomes ghosts, the world never resets.

Wilderness

• Intended to be more like other survival games.
• Players spawn in random locations.
• When players die they do not become ghosts.
• Dead players lose all their items and map information, and respawn at a new random location.