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BOMBANANA!Unofficial player guide
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BOMBANANA! Guide Launch troubleshooting
Launch troubleshooting

Fix “Fatal Error: IL2CPP”

Use this workaround only when the launch message is exactly “Fatal Error: IL2CPP” and reinstalling has not helped. It is a developer-posted Windows workaround, not a general fix for every crash or a fix for a Unity window that opens and closes. [1]

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Three monkeys coordinate to defuse a banana bomb.
Fan-made illustration

Official Windows steps

Security decision: the developer warns that turning off Smart App Control reduces a Windows protection and recommends this only for a game purchased from official Steam. Read the setting before changing it; this site did not change or test it. [1]
  1. Press Windows key + I to open Settings.
  2. Select Privacy & security.
  3. Open Windows Security.
  4. Select App & browser control.
  5. Open Smart App Control settings.
  6. Choose Off and confirm “Yes, I'm sure.”
  7. Restart the PC, then launch BOMBANANA! again.

The only stated success check is whether the game launches after the restart. If the exact IL2CPP message remains, stop treating it as a completed fix and report the outcome.

Linux and Proton are a separate case

EvidenceWhat it supports—and what it does not
Native LinuxOne player says native Linux support was removed after the Demo. The current FAQ lists Linux, while the live store gives Windows and macOS requirements. No official clarification, distribution, runtime or error text was found.
ProtonA different player says the release works with Proton, but gives no Proton build, distribution, launch option or reproducible setup. It is a compatibility report, not a recommended configuration or repair.

Do not apply the Windows Smart App Control change to a Linux/Proton problem. Record the distribution, desktop/runtime, Proton version, launch options, exact error and whether the game reaches a lobby; that is the minimum information missing from the public reports. [5] [3]

Report a failure with the symptom attached

If the official step fails, use Steam Community Hub’s Bug Reports forum or the official Discord. Include the exact message, OS, build, steps already tried and the result after restart. A September 5 post reporting only a Unity window that closes cannot establish an IL2CPP or Linux cause, so it should not be merged with this symptom. [2] [4]

Sources

  1. Fix for the 'Fatal Error: IL2CPP' Issue (pinned, Read Me First board, Steam Community) — official (posted by catty, [developer] badge); pinned post body: numbered fix steps and warning. Checked 2026-09-15. Published 2026-09-04.
  2. Bombanana FAQ (pinned, Read Me First board, Steam Community) — lefto-studio-tark-official; pinned FAQ post body, Q&A list; re-read 2026-09-15: modes, platform plans, Demo return, Server Browser / room codes. Checked 2026-09-15.
  3. BOMBANANA! on Steam (official store page) — lefto-studio-tark-official; store page body: description, modes, languages and requirements; re-read 2026-09-15 against the current store listing. Checked 2026-09-15.
  4. The game won't launch — player-launch-580555398933069514; Unity window briefly appears then closes; no OS or diagnosed cause given. Checked 2026-09-10. Published 2026-09-05.
  5. linux? (Steam Community discussion) — steam-linux-player-thread-580555047785531616; thread body and September 1 / September 10 replies: one player says Linux support was removed after the Demo; another says it works with Proton and links ProtonDB. Checked 2026-09-15. Published 2026-08-29.