Invincibility cheat code

The invincibility cheat code (R1, CIRCLE, CIRCLE, R1, R2, L1, L1, L2) is an in-game cheat code in Transformers for the PlayStation 2. The cheat code is one of three that can only be activated in the pause menu during gameplay in a level. It saves for as long as one level session; if you die, it's okay, but if you exit the level for any reason, the cheat is deactivated. You have to re-enter the code every time you enter a level.

Overview
The code allows the player to be immune from death during gameplay (with a few exceptions; see below). The player still loses health, but when health drops to 0 it resets to full health. The player also still receives knockouts, blows, etc.

Usage
This code could be particularly useful for speedrun practice; by taking away the handicap of death, one could practice difficult parts of the game involving heavy fire, such as boss battles. The code can also be useful for testing and glitchhunting; the process of testing can sometimes take very long periods of time and in that time lots of shots, etc. can be taken to the player, so using this code takes away the inconvenience of constant death. The code is of course also useful for messing around and feeling godlike.

The part that sometimes can suck about the code, by the way, is that suicide is almost impossible or at least extremely inconvenient without water being nearby. Suicide is useful for resuming from certain saved warp gates and returning to HQ. In situations where you're somewhat or completely stuck in a place where death is impossible, to return to HQ, you may just have to quit game and then go to HQ.

Deep water
If the player goes into deep enough water, the water quickly drains the player's energy. If the player's health reaches 0 from deep water draining, the player still dies. The developers probably made this exception for the cheat code to keep players from finding glitches down there. The deep water phenomenon can be hugely annoying when trying to do glitches such as out-of-bounds exploring, etc. However, the glitch can be helpful a lot of times when a quick reset or return to HQ is needed.

If you get hurt by any other means to get your health to 0 while you happen to be in deep water (usually by taking hit from a fall), your health can reset normally, though. This might be related to the deep water death delay glitch, in which without the cheat code, the player has an unusual extra delay before death while underwater due to a knockout that occurred down there. Theoretically, one could perhaps explore under deep water areas with this cheat code on by constantly hitting themselves with rocket launchers or other Mini-Cons that deliver player knockout at the correct timing, but it's unlikely that the player would be able to get very far up from the ground using this method.

If you're trying to test a certain glitch out that requires you to be in deep water for some short amount of time, it's imperative that you go in with a high enough amount of health to survive for that duration. If necessary, the player might need to reset their health by getting hit until health reaches 0, thus resetting back to full health.

The article Deep water hack covers the want for a hypothetical hack that would allow invincibility in deep water.

Out-of-bounds death floor
In every level, there is some means of getting out-of-bounds. You have to stay at a certain height while out-of-bounds though; if you go too low, you will hit an out-of-bounds death floor. Hitting this causes the player to immediately die without further ado. These were likely inserted in the game to prevent an infinite out-of-bounds fall in the case that a player was actually to be pushed out of bounds somehow. Even with the invincibility code on, the player can still die by hitting an out-of-bounds death floor, so it's still something the player should be aware of when doing OoB exploring.

Cybertron
Cybertron works almost completely differently from other levels in almost every respect. The invincibility cheat code can be activated in Cybertron (since the pause screen is still the same), but the code does nothing in this level. If your health reaches 0 you still get the bad ending; it does not reset.