Boss Guide: Part 2
The Bloat is a much harder version of Peep because of the fact that the eyes travel around the level right from the beginning of the fight. You constantly have to dodge the eyes and fight The Bloat at the same time, and it can be difficult to juggle the two tasks. He contains all the same attacks as Peep with the exception of a beam that he shoots from his eye sockets to the left, right, or front depending on where the player is standing. That means the best spot to attack The Bloat is from behind so he doesn't use his powerful new attack.
The Carrion Queen
The Carrion Queen acts just like Chub, but she has to be shot in the tail or fed bombs to damage her. As she moves around she spawns red poop, which damages the player if touched and comes back even after being destroyed. As her health reaches the halfway point, she begins to travel in a diagonal pattern like The Hollow. This makes it harder to hit the tail, so focus more on defense and hope to get a few shots in here and there. The red poop might be the biggest threat here just because of the way it regenerates, so keep an eye out on the level to make sure you don't bump into anything.
Loki uses some basic projectile attacks in which he either shoots four or eight projectiles in simple plus and X patterns. He also likes to teleport around the room, which can cause some trouble. Lastly, he will occasionally summon some Boom Flies, which should be killed quickly when they're far away from the player. There's not a whole lot of strategy to this fight, just dodge the projectile attacks and keep moving so he doesn't teleport right next to you.
There are many ways to attack Mom, so damaging her isn't a huge deal. Defense is the most important thing, because she sends all kinds of enemies after the player and stomps her foot from above. The stomp attack can be easily avoided if you pay attention to the shadow on the ground, and it provides a great opportunity to attack the foot if you dodge it. You can also shoot the flesh that appears on the sides of the screen or the eye. All of these things damage Mom. Just be sure to eliminate the additional enemies first, because you want to be able to focus on Mom. Also, don't get too close to the sides of the screen or Mom will swipe at the player with her hand. Also, remember to use bombs as a weapon. Place them on the sides of the screen to hurt Mom when the flesh or eye appears.
Monstro II has a Brimstone attack that he shoots left or right, and also jumps up and lands like his first form. When he lands he has new attacks though - he will either shoots in eight directions or Spawns suckers that shoot out projectiles when defeated. The easiest way to beat Monstro II is to get in front of him, bait his Brimstone attack (wait until he smiles), and then go behind him and shoot. If you carefully repeat this process his jump attacks don't factor into the fight at all.
The player must beat Mom one time to unlock War, one of the four Horsemen of the Apocalypse. Like other Horsemen boss fights, this has two phases. War charges left or right and passes through the screen three times and then shoots in eight directions. He also summons troll bombs, much like the Anarchist Cookbook. Those are his only attacks in the first phase, and the troll bombs are the only big threat. Avoid those and you should get to phase two with relative ease.
When the player removes half of War's health, he goes it alone without the horse and moves very fast around the level. Eventually he needs to catch his breath, and that opens up the perfect opportunity to attack. If you have a slow character, this phase of the fight might prove troublesome.
The Blastocyst boss fight is all about dodging normal projectile shots (in four- and eight-shot variations) and shooting at Blastocyst. Sounds simple enough, but he splits up into smaller parts the more you attack. Thus, you want to focus on one smaller Blastocyst when it splits and leave the other big one in tact until you finish off the rest of the parts. Basically, the less Blastocyst enemies the better.
The player must beat Mom one time to unlock Death, one of the four Horsemen of the Apocalypse. Again, it's a Horsemen fight which means two phases. Death shoots scythes that travel around the level or chase the player. In the case of the latter, you can either try to dodge or shoot the scythes. Depending on where you are and how much damage you do, shooting the scythes may be easier. Death also has the Hourglass item, which slows movement and tears.
The second phase of the fight begins when Death reaches half health. Death separates from his horse and now the horse travels across the screen just like the War boss fight. Shooting the horse does not damage Death, but it can be defeated. Meanwhile, Death will walk around and summon Knights to help him. Get rid of the Knights, avoid the horse, and attack Death. You really don't have to defeat the horse, but you can do so if you feel like it's necessary.
The Mom's Heart boss fight begins with two eyes on the left and right sides respectively. Immediately get rid of the eyes and any additional enemies Mom's Heart summons after that. All the while, the Heart will be shooting projectiles, so you have to dodge those and shoot the additional enemies at the same time. Once that's all been dealt with, Mom's Heart will appear in the center of the screen. If you can time it correctly, place a Bomb in the middle just as Mom's Heart is about to appear to do a lot of damage.
When Mom's Heart appears in the center, it shoots blood projectiles in a few different patterns that are very difficult to avoid. You have to put your back against the wall in some spots just to give yourself enough room to dodge. Keep attacking the heart in the center as you avoid the projectiles, as it's your best opportunity to attack. Eventually the pattern will repeat again and Mom's Heart will summon more enemies. It's a much tougher boss fight in Rebirth than the original game, but with enough practice and perseverance you should be able to beat Mom's Heart. Be careful though, as Mom's Heart shoots projectiles one last time as it dies, and that would be an awful way for the player to die.
The Scolex boss fight is much like the Pin boss fight, with a few tweaks. He still goes in and out of the ground, but the attacks are a bit more dangerous. Scolex fires three explosive shots when he pops out of the ground and looks around. His tail will also pop out of the ground at times and shoot blood similar to Monstro. The only way to damage Scolex is to attack the tail, but he has little health compared to some other boss fights.