Over a decade after the release ofPortal 2, fans are once again exploring the Aperture facility in the hopes of escaping the seemingly endless puzzles inPortal: Revolution.While this is an unofficial game-sized mod to the original hit title, the puzzles in this game are some of the most challenging to date.

To get through Chapter Four, you’ll need quick reaction times and the ability to out-think several turrets that would otherwise turn you into Swiss cheese. In this chapter, you’ll have both portals to make solving the puzzles a little bit easier. That being said, Portal: Revolution introduces new elements to keep you on your toes.

A screenshot from Portal: Revolution showing the player character aiming the Portal gun at a red X on the ceiling above a raised platform.

Turret Playground

Follow the pathuntil you enter an area where Stirling starts talking and eventually opens the wall next to you.Shoot a portal on the white wall in the openingand thenshoot the opposite color on the far wallbehind the turret.Go throughand either tip the turret over from the side or leave it alone.

In the adjacent room,shoot either color underneath both turretsto have them fall through and into a room away from you. Then,grab the cube and place it on the big red buttonto open the exit. In the next room,shoot one color portal on the Xabove the left turret andthe other color underneath the right turreton the ground.

A screenshot from Portal Revolution showing the player aiming the portal gun above some turrets on a raised platform on the opposite side of the room.

This willcause them to fall into each otheruntil they’re both knocked over. Walk to the edge of the raised platform andshoot a portal into the wall behind the last turret, then one on the ground to get behind it.Push the turret from the sideto knock it over.

Jump back to the ground andshoot a portal on the red Xabove the raised platform where the turret was. Shoot theopposite color on the ground and go through itso you land on the raised platform. Jump over to where the cube is located andpick it upbeforetaking it back to the first platform.

A screenshot from Portal: Revolution showing the player character looking at a red button with a portal on the far opposite wall and gel falling on a floor across a gap.

Then,shoot a portal into the high wallon the furthest part of the chamber beforeshooting another on the groundbelow you.Grab the cube and jump through, launching yourself to the red button.Drop the cube on the button, then go back to the first raised platform.

Jump across the platforms andgo through the exitinto the next testing area.

A screenshot from Portal: Revolution showing the player character looking at two portals on slanted walls, with a cube in the air being thrown from the portal

In the next testing area,shoot a portal of one color underneath the cube dispenserand thenshoot another above one of the turretsacross the room. Then,press the button to drop a cube through the portaland knock over the turret.Repeat this processuntil both turrets are deactivated.

Once defeated,walk through the hallway and then turn to your leftto see a high wall behind the turrets.Shoot the portal color that’s not under the dispenseron that wall to send cubes flying into the turrets.Repeat this processuntil both turrets are deactivated.

A screenshot from Portal Revolution showing the player character holding a storage cube looking through an orange portal with a door open above it.

Next,shoot a portal on the ceiling above the far pathwayand drop a cube through it.Ensure that it lands safely on the pathwaybefore going through the dispenser portal yourself.Take the cube to the large buttonand drop it to open the exit. Go through and thenget on the elevator.

Excursion Funnel Flings

When you walk into the next chamber,go over to the large red button and stand on itto activate the tractor beam.Shoot a portal underneath it, and then shoot the opposite colour on the wall next to you, opposite of the gel dispenser.

Oncethe tractor beam catches geland takes it through the portal,move the portalfrom the wall beside you to the slanted wall. Then step off the button and allow the gel to be launched to the edge of the pathway. Next,use the tractor beam to catch the ballfalling in the water andbring it backto you. Drop it on the button.

A screenshot from Portal Revolution showing the player character aiming their portal at a launcher with blue and orange portals seen in the distance.

Gowalk into the tractor beamand wait until you’re pulled to the highest point. Then,shoot the opposite color of the portal under youacross from the gel. This time,drop the gel when it goes over the ballto cause it to bounce. While falling,shoot the portal you just used on the slanted wallto launch across the room.

Press the button on the other side of the roomto raise the square floorfrom the water under the dispenser. This will also cause the ball to disappear if it hasn’t already.Place one color portal on the newly raised platformandthe other on the slanted wallon the other side of the room.

A screenshot from Portal Revolution showing the player standing in the Crisis Core room with the big red button

Activate the button againto send a ball from the dispenser through the portal,launching it to your sideof the room. Let the ball land in the input or place it there yourself toopen the exit door, allowing you toget on the elevator.

If you canget the ball to land in the input slot when you launch itfrom the portal,you’ll get an achievement.

Cleansing Field Loop

Go along the path until you get to a round door that won’t open.Shoot a portal on the white wallsnext to you, and thenaim one through the gap in the wallto get into the testing area. Once inside,shoot a portal on the wall with the grated areaandthen one on the ground or wall to get up there.

Once on the grated area,shoot one portal on the nearby slanted wallandone on the ground. Jump through the portal on the ground tolaunch yourself across the gapto the area with the button.Shoot one portal underneath the dispenserandthe other on the slanted wall on the far right slanted wallwhen facing the button.

Press the button to dispense a bouncy cubebeforeshooting the dispenser portal on the slanted wallnear the button once it goes through. This will launch the cube and create a loop going through the cleansing field. Once the cube has gone through the portal near you,shoot the opposite color on the slanted wallahead of you.

Once the cube lands next to you,place it on the buttonto activate the exit door. Then,go back to the starting area and use two portalsto get back to the grated area.Shoot one portal on the groundbelow you andthe other on the slanted wallon the wall opposite of you.

Make note of which portal is on the ground as youjump throughit, and thenshoot it at the slanted wallright before you hit it. This will create a loop that will allow you toplace the portal that’s behind you on the slanted wallto your left.This should launch you to the exit platform,where you can get on the elevator.

Power Switches

Walk along the path until you get to a door that opens halfway, thenshoot a portal through to the white wallon the inside andthe other one behind you. Use it to get into the next area and follow the path to a room with a conveyor belt.Shoot a portal on the wall above the conveyor beltandone on the ground-level wallbefore going through.

In the room with the broken window,shoot a portal on the far wallin the chamber andone beside youto get inside. Go through the energy field in front of you and activate the switch to turn off the power. Then,go back through the deactivated energy fieldandshoot a portal on the upper levelon the left.

Shoot the opposite color on the same side of the energy fieldas the power switch. Thenturn the power back on, go through, anddispense a cube before taking it with you back. Turn the power off,place the cube on the button, thenturn the power back on.

When the door opens,shoot a portal throughandthen turn off the power. Take the cube through the portal and into the second room, where you can simplycarry it above you and place it on the button. Then, go back through andturn the power on.

Shoot one portal on the groundandthe other on the wall sticking out. Go through both tolaunch yourself across the roomand to the exit door. After going through the energy field,go through the hole in the wall and use portalson the white walls next to the pipes. You’ll need tojump over the gapinto them.

At the end of the pipe,shoot a portal through the broken glassonto the concrete wall, thenjump through the portalon the white wall behind you.Continue walking until you see an openingon the right side of the walkway andjump downbefore going through the energy field.

In the next room,shoot a portal of one color on the far wallahead of you andthe opposite color on the wall next to it. Step on the launcher to bethrown into one portal and out the other. Once you’ve landed,press the button to drop a cubeand have it go through the same process.

Take the cube down a level and place it there beforeturning off the power. Shoot a portal on a wall near youandone on the wall near the start. Take the cube to thestarting area and place it on the launcherbefore going back through.Shoot one color portal on the wall ahead of the launcherandone on the slanted wall in the water.

Turn on the power to launch the cubethrough the portals andonto the button. Next,shoot a portal on the slanted wall near youand thenone at the startbefore going through. Take note of which portal is behind you andshoot it at the wall in front of the launcher. Step on the launcher andbe flung into the exit door.

Follow the path anduse portals once more to get through a broken windowand into a lower area. Continue walking until you get into a chamber.

The Spire Core

When you enter a room with a door that won’t open,shoot a portal on the wall near youand theother one on the ceiling behind it. Continuewalking past the brief PowerPointand thenfollow the path through the energy field.

The Spire Core is straightforwardand mainly requires that youfollow the orders of Stirlingas he runs his tests using the Core. When you’reasked to step inside the specimen chamber, do so.