What to know
Exactly three players
BOMBANANA! is designed around exactly three players. Steam describes a three-player bomb defusal team, and the feature list says there are no more and no less than three monkeys required.
That makes the player count unusually important. In many co-op games, player count is just a lobby setting; in BOMBANANA!, the number of players is tied directly to the blind, mute, and deaf role structure.
Why the game uses three roles
Each role appears to hold a different piece of the puzzle. One player can interact with the bomb, one has the manual, and one can help translate what is happening.
The fixed team size lets the game create confusion and cooperation at the same time. If one role were missing, the communication chain described on Steam would change completely.
Solo, duo, and four-player status
Solo play is not confirmed. Duo play is not confirmed. Four-player mode is not confirmed. The confirmed setup is exactly three players.
If Lefto Studio later adds optional modes, this page should be updated. Until then, players should plan around a three-person group.
Where to go next
For role details, use the multiplayer page. For whether the demo can be played before release, use the demo page. For platform and crossplay questions, use the platforms page.
Those pages cover adjacent questions without changing the core answer here: BOMBANANA! is a three-player co-op game.
Planning a group
If you are preparing to play BOMBANANA!, plan for a full group of three friends rather than assuming the game will scale down. The official Steam messaging repeatedly points to a three-monkey setup.
A good group should be ready for communication mistakes, role confusion, and repeated attempts. The game is a party-style co-op puzzle, so the right group matters almost as much as the player count.