Invulnerability

Invulnerability is the state where the player is immune against enemy attacks. In most cases, the player's character flashes colors. Below is a list of various ways a player can achieve this state.

Temporary

• Starting a mission
• Spawning from death
• Entering a new room
• Exiting a room: Normally, any enemies on-screen instantly die when the player triggers the exit. Those that are still alive can attack the player but won't be able to kill them.
• Knocked over: Whenever a player is hit by an Ohumein-Conga, a Japanese Tank Soldier, The Iron's spinning blades (only while it is being deployed), or Mecha Allen or is damaged as Ralf. This occurs during and a bit after the player lifts themselves up.
• Getting hit: Only in games where the player has a health bar.
• Entering a Slug: This includes animal Slugs.
• Exiting a Slug: The player is invulnerable when flipping and a bit after landing.
• Getting hit in a Slug: The exception is the Bradley which has no I-frames.
• Transforming/Reverting: The character is invulnerable during and a bit after transforming.
• Starting Metallish: Collecting an Emblem gives a few I-frames.
• Using Clark's Argentine Backbreaker: Clark is invulnerable when performing the move and a bit after throwing the enemy.

Permanent

• Using Debug Mode: Turning "ムテキ" ("Muteki", meaning "Invincibility" in Japanese) on gives permanent invulnerability except for pit falls and crushing .
• Using Cheats: Depending on the game and cheat, certain attacks can hurt or knock the player.
• Super Devil Mode: Only in Metal Slug: 1st Mission, reaching the SD rank rewards the player with permanent invulnerability. This excludes falling in a pit, touching spikes, or getting crushed.