The Evil Within features staple survival horror boss fights that force players into uncomfortable situations to see how they'll react and overcome the challenges. Some of these challenges are more difficult than others, and some are straight-up broken fights if players use the right tactics.
The most interesting fights have multiple answers to them and create a sense of victory in the player afterward. Ranking the fights by creativity and immersion are the best parameters since that's what survival horror is all about. In other words, the best fights make the player feel like they're directly involved in the battle and the worse ones make players feel disconnected from the events happening on screen.
Sentinel
Sentinel is a simple beast, with a simple boss fight. The creature will run into bushes around the arena and attempt a surprise charge attack on the player that can kill in two hits if they're not careful. Players can predict where the attack will come from by watching the bushes for movement since that indicates where Sentinel will appear from.
Players can also prevent the rush attack by firing explosive bolts into the bushes to stagger Sentinel. If they can't prevent the attack, it's best to sidestep its advances since it's pretty clumsy, even though it's fast. The last tip is to aim for its face since that's its weak point. Shotgun shells and bolts from the Agony Crossbow put a stop to his endless offense.
Zehn And Neun
These two titans are extremely susceptible to hiding and leading them around the map. They can throw projectiles that deal a lot of damage, so it's important to find cover while moving around. There're certain spots the player can hide under to lure them out so Joseph can get a clear shot on them.
Once their attention is on Oda, set a few traps with the crossbow to shock them to death and focus damage on one at a time. After a bit of patience, they'll be easily defeated. Staying hidden may seem like a cowardly play, but these two have no way of beating it so it's the safest bet.
Heresy
Powerful ammunition is a must-have for this boss. Machine gun fire and magnum fire dislodge it from the bus pretty easily. A big mistake players make during this fight is trying to damage Heresy when it has been dislodged from its walls. Bullets actually just pass through it during this time so be sure not to waste ammo trying to hit something that can't be hit.
This boss battle is also one of the few times that machine gun ammo is guaranteed to spawn. It usually spawns in the back of the bus so try to check back there between rounds of the battle since that ammo is so valuable. Lastly, aim for its face since that's its weakest point.
Quell
Before the Quell fight even starts, it sets itself up for a sneak attack on the player that they can thwart. Its head peaks out from a spot in the tunnel ceiling and if it's shot, it'll get scared and run to the boss arena. Once the fight begins, Quell is a mobile enemy that can obscure itself and attack from seemingly anywhere.
These attacks all have clear counters that are a bit more difficult to execute without practice. For example, its sliding attack can be dodged with a well-timed neutral dodge that strafes around it. Secondly, when it turns itself invisible, players can follow the trail of larval spawn and still attack it. Locking it down with freeze and shock bolts makes this even easier since it's weak to those attacks. Following up with magnum and sniper bullets should knock it out quickly.
Ruvik
The fight against Ruvik is a riveting ride around the arena that keeps ramping up in intensity. The first step is to run from him along certain areas. The trick is to start by going to the left and wait for his attack to pass. Next, hug the right walls until coming to another building. Repeat this process until Sebastian falls into a truck in a cutscene.
From here, the battle becomes a spray and pray encounter. Targets will appear on Ruvik's limbs indicating where to aim. When no targets appear, his head is his weakest point. After this segment, the scene will transition and players will have to take aim with a rocket launcher on Ruvik. It takes a few hits to stun him and the rocket launcher has limited uses so be careful with the shots given.
Laura
As a first boss fight, this one teaches the player some important lessons about the game moving forward. The battle arena of the Laura fight is full of obstacles, traps, and mechanisms the player can use to their advantage to defeat her if they pay enough attention.
The best approach is to conserve ammo. This fight can be completed from start to finish without firing a single round. This is because Laura is weak to fire and will writhe in pain if players hit her with a torch. After hitting her with a torch, lure her into an incinerator room when she gives chase, and pull the switch to drop her into the fire below. Repeat this cycle until she's defeated.
Amalgam
Amalgam is a straightforward fight with creative elements strewn about the battle. The best approach is to keep distance and snipe the creature from out of sight. Firing once at a time at its eye can stun it momentarily but freeze arrows can do a better job at keeping it immobile.
Hiding behind pillars and firing at a slow rate should keep the Amalgam from pressuring too hard but if it fails, there's a room players can run to in order to regroup and find ammo. Eventually, the Amalgam will reach in and scoop the player out of the room but it doesn't do too much damage so don't be afraid to get scooped. The process of sniping Amalgam just continues until it's defeated.
Keeper
This fight isn't too much of an actual battle and seems more like a battle with Pyramid Head from the Silent Hill series. The full goal of this battle is to shut off three valves to enter the catacombs below. Killing Keeper is pretty simple between the valves and only takes two shots from explosive bolts to go down each time. He can also be trapped with shock bolts that keep him in place while the player goes and finds the valves to progress.
Laura (Again)
The second Laura fight has a similar premise to the first one of luring Laura into fire to burn her, but expands upon the idea. In this battle, she's a lot more dynamic and the player has to think on their feet more to lure her into the proper traps. The best boss fights of The Evil Within make players think on the fly and force difficult decisions on them, which makes this one stand out among the simpler ones.
In the boss arena, there're tons of pipes that shoot flames downwards and can be triggered with a shot to their levers from the player's gun. During the fight, keep an eye out for these stray pipes since they're not as obvious as the other walls of fire and incinerator pits.