The Thermonuclear Bomb is a deployable weapon that is largely traditional to the Raiden Series. It is a simple bomb that despite is capable of destroying many enemies at once as well as dealing significant damage amongst bosses. The weapon is often indicated by a red "B" power-up. Unlike primary and secondary weapons, the bomb can only be used a limited amount of times, as the player will need to stockpile them thoughtout each of the games.
The thermonuclear bomb was originally the only bomb (and limited weapon) in the original Raiden (its initial appearance. It is a simple, yet powerful bomb-type weapon that unleashes a huge explosion over significant portion of the field of the screen. Because of this function, the bomb proves very useful amongst multiple enemies (especially those packed into dense clusters). The bomb is also useful for draining a significant portion of any bosses' health, as it will allow the player to destroy them much quicker than with just there standard weapons.
The bombs are indicated by a triangular power-up with a large red "B" over it. The power-ups will also move in a different movement pattern than those of primary or secondary weapons, making it significantly harder to obtain.
Players will need to know that unlike the primary and secondary weapons usable in the Raiden series, the bomb's usage is limited. Fortunately, the player has 3 stocked into their fighter by default at the beginning of the game and foreach initial checkpoint after previously losing a ship. It should also be noted that besides the limited uses, the player is granted a bonus at the end of each mission for each bomb left in their stockpile, suggesting that the player should use them sparingly.
The thermonuclear bomb has perhaps the largest damage output of all the weapons within both Raiden and its sequel. Being able severely damage numerous bosses. Besides it damage output, the radius of the explosion produced by the bomb is also formidable as well, making it a great choice for dealing with large clusters of cranassians and hazardous obstacles.
The obvious downside to the bomb is the limited usage, something that is nonexistent to the other traditional weapons. Because of this, the player is given 3 bombs by default for safety precautions and is restocked with them each time they lose a fighter.
The fact that the bombs are able to add bonus for each one saved into the player's stockpile at the end of each mission could also be considered a downside to the weapon, as the mechanic is attempting to encourage the player to limit their usage of the bomb and to only use it under absolute necessary conditions.