Blue Bomber

Blue Bomber is Challenge #23 introduced in The Binding of Isaac: Afterbirth. The challenge is started as ??? with, , , and. No Treasure Rooms. The goal is to defeat Satan.

Difficulty
??? is blindfolded and cannot fire tears. Players will have to use Kamikaze! and bombs to defeat enemies, with Brother Bobby generally as a last resort. Because Pyromaniac prevents damage from being taken from explosions, players can use Kamikaze! whenever they please. Using it as an offensive weapon can be very dangerous, as the player will have to closely approach enemies, increasing the chance of taking damage.

As ???, health is crucial due to the absence and inability to obtain Red Heart containers. Any form of damage is threatening, as hearts may be hard to replenish.


 * This challenge has become significantly easier with the buff to Kamikaze! making it go from 40 damage to a staggering 185, and increasing the explosion radius.

Strategies

 * Finding an item which revives ??? as another character, like or  will make the run trivial: After reviving ??? will be able to gain Red Heart containers, therefore heal infinitely as long as there are extra lives, effectively making him invulnerable.  will also work, though the odds of getting it are small.
 * can no longer gain red hearts, making it pointless to take Judas' Shadow and turn into him.
 * With Kamikaze!, rooms can be skipped without having to clear them. This can especially be useful against larger and more challenging rooms.
 * Broken Remote allows for essentially infinitely reusable teleportation, enabling entire floors to be skipped, except for boss fights.
 * The player should use bombs for boss fights or harder enemies. Due to, not only do bombs deal increased damage, but they also have a far larger blast radius.
 * By dropping a bomb then using Kamikaze! to propel the bomb towards enemies, ??? can safely deal damage from afar with relative ease.
 * Kamikaze! effectively gives ??? infinite explosives, so it’s a good idea to blow up rocks to look for Crawl Spaces, and ??? can search for Secret Rooms at no cost. Also, the player can blow up Tinted Rocks, Skulls, and Blue/Purple Fire Places, which may contain Soul/Black Hearts. However, be careful about blowing up Skulls before clearing a room, because they may contain Hosts.
 * Be careful about bombing objects that could deal damage to ??? upon destruction. It's risky to use Kamikaze! around Mushrooms since they may release damaging gas or around Polyps as they may explode into bullets. It may behoove the player to destroy these obstacles via bombs to prevent such a scenario from occurring.
 * The player should not replace/reroll Kamikaze! as without it, the challenge will be extremely difficult or even impossible. They should be very careful around Dice Rooms,, and certain dice items.
 * Familiars and are useful in this challenge, since it allows the player to deal with enemies that are dangerous up close more easily.
 * and are especially useful as they gain increased damage from Mr. Mega, while Pyromaniac will protect ??? if they explode close by.
 * in his level 4 state allows the player to keep enemies at a distance while Bumbo chases them down and does contact damage.
 * is preferred over since the shield will trigger every time ??? takes damage, allowing him to get up close to spam Kamikaze! safely for a brief moment.
 * Only The Negative appears after defeating Mom.
 * When fighting Mom, a reliable strategy is to stand in the corner and play defensive. Whenever she exposes herself from nearby doors, go to them and use Kamikaze! from the side. ??? cannot be hurt by her (and Satan's) stomping attack (see ), but watch out for its knockback.
 * Due to the immunity to Mom's stomping attack, Mom's Toenail has improved usefulness.
 * Pyromaniac no longer grants immunity to stomping attacks.
 * Items that modify bombs, such as, , and are especially useful, as they provide a greater range for the detonation, a poison effect, and damage to the entire room, respectively.
 * provide an unlimited source of pickups, including Soul Hearts.
 * Gaining flight allows ??? to quickly navigate rooms, to avoid having to use to reach faraway enemies, and to better maneuver around for Kamikaze! usage.
 * , which grants flight, can be found in Secret Rooms.
 * , which is incredibly useful for blocking shots, can be found in Angel Rooms. Since ??? can't fire tears, focus on defending from enemy projectiles. This is especially useful in the battles with Mom's Heart/It Lives and Satan.
 * Sleeping in a bed will give 3 Soul Hearts.
 * Since ??? is unable to use Red Heart pickups, is extraordinarily useful as he gathers the hearts and converts them into Black Hearts and Soul Hearts, as well as the occasional friendly blue spider.
 * Dark Bum now also has a chance to drop pills, cards, and runes, which can include, Balls of Steel, or , to name a few.
 * are especially useful. Every room entered will confuse enemies and with Kamikaze! they will not attack ??? as long as the fire buttons aren't pressed.
 * Acquiring makes this challenge far easier. Allowing bomb-related items such as  and  to spawn in Shops, Devil/Angel Rooms and as Boss rewards, these items allow Isaac to hit enemies passively from afar or use an unlimited -style effect, especially powerful when combined with.
 * is another great item that makes the challenge easier. You get 2 Black Hearts and its passive activates across the run, giving you flight and a 10-second shield every 40 seconds. Paired with shield already mentioned, you can activate Kamikaze enough to kill most bosses without taking any damage.
 * is useful for reducing the risk of being overrun by fast enemies, and makes it far easier to dodge enemy projectiles when weaving towards them.
 * can be a run-winning item as it triggers a 4-way brimstone at every kamikaze explosion due to their new synergy. This can clear out entire rooms for you and is very helpful in dealing with certain enemies which previously had to be dealt with with the tears of familiars as brother bobby

Reward
Note that Golden Bombs have fixed appearances in certain room layouts even before this achievement is unlocked. The achievement simply allows them to spawn in place of other bombs, like Golden Keys.

Trivia

 * The title for this challenge is a possible reference to Mega Man, as he is commonly known as the Blue Bomber.