Bombs can be placed at Isaac's feet by pressing E, Shift, or Ctrl and will detonate after 2 seconds.
Bombs deal one full heart of damage to Isaac, unless the player has The Wafer.
Bombs are solid and can be pushed by Isaac, enemies, and tears for tricky shots and offensive purposes.
A normal bomb has an approximate blast radius of 2 squares when it detonates.
Any active bomb will reset its timer when another room is entered. A bomb that had its timer reset by exiting and re-entering a room will have an increased blast radius, identical to that of the bomb dropped by Mr. Boom. This can be used to the player's advantage by destroying more rocks than usual.
Bombs have various purposes which include:
- Destroying rocks
- Falling rocks over to form bridges over pits
- Breaking into Secret Rooms and Super Secret Rooms
- Breaking normal doors (Will not break other doors or any doors in The Chest.)
- Damaging enemies, for 60 damage by default
- Destroying Slot Machines, Fortune Telling Machines, Shell Games, Beggars and Blood Donation Machines.
- Using the bomb explosion to push coins, hearts, bomb pickups or keys away from locations where they're surrounded by spikes.
The Mr. Boom activated item will drop a large bomb. Large bombs are upgraded bombs that deal more damage (+50, meaning 110 damage) to enemies and have a larger blast radius (3-4 squares). Bombs can be permanently replaced by large bombs by collecting the Mr. Mega item.
|Bobby-Bomb||Bombs follow nearby enemies, adds 5 bombs to the player's inventory|
|Mr. Mega||Upgrades all bombs to large bombs, adds 5 bombs|
|Boom!||Adds 10 bombs to the player's inventory|
|Added in Wrath of the Lamb|
|Pyro||Adds 99 bombs to the player's inventory|
|Bob's Curse||Bombs poison monsters caught in the explosion, adds 5 bombs|
Bombs can be picked up when found (unless lit) and will be added to Isaac's inventory. Each bomb adds 1 to the total number of bombs carried, up to a maximum of 99. Special 1+1 Free Bombs can also be found which increase the number by 2. These have a 1/7 chance of replacing a normal Bomb.
The Troll Bomb is a bomb that has a 10% chance to replace normal Bombs. They are also dropped by Pride, War, and other enemies. They cannot be picked up, and will explode a few seconds after being dropped. They also have an increased blast radius compared to regular Bombs.
Troll bombs are immune to Isaac's tears (not to be confused with lit normal bombs which aren't) but are solid and can be pushed around before exploding the player or enemies.
A Troll bomb explosion will deal normal bomb damage to enemies and 1 full heart damage to Isaac, like normal bombs.
Troll bombs are a reference to the popular internet meme, the Trollface. It's as if the bomb is "trolling" the player when they are dropped.
Using the item Anarchist's cookbook will summon 6 troll bombs around the room.
Touching a Troll Bomb in the Wrath of the Lamb DLC now displays the message TROLOLOLO at the bottom right of the screen, referencing Eduard Khil's famous "I Am Very Happy Because I Am Finally Back Home", more commonly known as "Trololo".
Super Troll Bomb
Added in the Wrath of The Lamb DLC, Super Troll Bombs can follow Isaac over obstacles and will actively chase him until they explode a few seconds after they spawn. They have a 1/50 chance of spawning instead of a Bomb pickup but are more commonly found in Red Chests. These are also spawned by Super Pride and Super Wrath.
Alternatives to bombs
Sometimes, instead of having to spend a bomb from an inventory, it's possible to break rocks, open regular doors or open secret rooms by other means.
Items that mitigate the need for bombs
- Anarchist Cookbook or The Tower Tarot Card (Spawns Troll Bombs in random locations.
- Mr. Boom (Drops a large bomb; takes two rooms to recharge)
- Explosive Diarrhea! Pill (makes you randomly drop lit bombs on the ground, but only temporarily. Due to a bug, this pill does not spawn if the player has Wrath of The Lamb installed)
- Doctor's Remote (Launches a guided missile; takes 3 rooms to recharge)
- X-Ray Vision (Automatically reveals and opens Secret Rooms)
- Notched Axe (Breaks a rock in front of Isaac; takes a room to recharge)
- The Nail (Allows Isaac to break rocks by walking over them; takes 6 rooms to recharge)
- Bob's Rotten Head (Throws a poison bomb; takes 3 rooms to recharge)
- Best Friend (Deploys an exploding Isaac doll; takes 3 rooms to recharge)
- Items that grant Flight.
- The Ladder (Lets Isaac walk over one-block Pits; some rooms have chests behind a rock on one side and a gap on another side)
- Treasure Map, Crystal Ball, The Sun and The World Tarot Cards eliminate guess work by revealing the location of Secret Rooms.
Also, a carefully placed bomb can take care of multiple targets.
Items that provide an unlimited amount of explosions
- IPECAC (gives tears poison bomb effect)
- Kamikaze! (causes you to lose one heart, unless you have an invincibility effect)
- Dr. Fetus (replaces tears with bombs)
- Epic Fetus (replaces tears with explosive missiles)
Some of these enemies can be tricky to make an explosive attack at desired location while it's easier for others. Many enemies in Wrath of the Lamb have green explosive shots which are easy to guide where you want them to.
Carrying this trinket at any time slightly increases the odds that a bomb-type item will drop upon finishing a room.
The Burnt Penny
While holding this trinket, every coin collected has a 50% chance of dropping a free bomb for the player.