This guide tries to explain some of the ways you can get a wrong timeline end on different chambers in portal reloaded. A wrong timeline end is where the developer has not inteded for you to finish the chamber when in that timeline. Some unique dialogue is played and you are prompted to go through a time portal to get to the correct timeline.

You need to get the cube when you are in the future timeline, then put the cube on the stairs so it's tilted. Bhop on the upper part of the cube (you need to get some weird boost from the cube) and grab the cube right after jumping on it. Then simply land on the elevator, put the cube on the button and you are done.

For this chamber you need to get the cube when in the future timeline, tilt it using the hole on the plateau. Put the cube in the corner and jump up on the cube, jump up on the plateau and grab the cube. Then just put the cube on the button and you are done.

To get to the platform in the video, simply put a portal on the tilted surface facing the room with the time portal button in it, put your other portal in the pit and jump through. When you are on the platform (in the future timeline) put your portal on the same two surfaces and jump through, you need to do some strafing to get to the pit and then when you get through the portals you need to hold whichever button you use to get closer to the platform (often A or D). Once up you can just go through the door.

This chamber is probably the easiest, you just have to put a portal on the ground close to the end platform and one under you, jump through and do some strafing to get to the end platform and you're done.

When in the future timeline, you need to do some decent Bhopping while pressing the button when you pass it. Get through the fizzler and shoot a portal under the cube dispenser and one on the portal surface facing you. Catch the cube and put it on the button, and you're done.

When in the present timeline, put a portal a bit right of the laser, put your other portal at the far right of the chamber wall and if you've done it right the laser will autocorrect to the laser receiver.

Thanks to Nekai_Nekko!
Here you need to be in the present timeline and get the laser cube. Put the timeportal as far left of the door as possible, face the laser cube towards the laser reciever in the future. Go through the timeportal and grab the future version of the laser cube, shoot one portal where the laser is and the other to your right in the middle of the wall. Put the laser cube so the laser goes through both of the laser recievers and the present version of the laser cube. Then just walk through the door.

This one is a bit tricky, when in the future timeline you put a portal almost at the highest point of the wall (you don't want to hit your head on the ceiling). Bhop through and land on the platform to your left. Get the laser cube, put one portal where the laser is and one facing the laser receiver. Make sure the laser receiver is getting the laser, grab the cube and jump through the portal receiving the laser and land up on the chamber sign. Jump down to the edge of the window and then just jump to the end platform, put the cube on the button and you're done.

Credits to Antkro for showing me this.

This one has too many portals for me to explain without it being wack, so just watch the video if you are interested in how to get the wrong timeline :).

When in the future timeline, stand facing the light bridge and shoot a portal on the wall above you almost at the highest point and to the right. Put your other portal on the wall close to you, bhop through to the left around the corner and land on the camera. It can be a bit tricky to stop on the camera but once you are there simply jump down to the highest elevator and go to the end.

This one you have to be in the present timeline, you need to have the cube with you on the button and a portal with a horizontal light bridge. Stand on the cube, jump and put the light bridge so it would collide with you and then you will get pushed up onto the light bridge.

Here you should be in the future timeline, put a portal on the funnel and one on a wall on the bottom row. Crouch fly (crouch fly tutorial on the end of this guide) to the cube button and press it, catch the cube and fly up the the big button and put the cube there. Then you're done.

Here you do everything normal up to the point where you have the future cube in the present. You then put a funnel towards the button on the wall and throw the cube into the funnel. When the door opens the future door will also open for some reason, so just walk through you time portal so you are in the future. If you wan't the dialogue that comes when finishing a chamber in the wrong timeline, you have to wait for him to finish speaking until you go through the door.

This one is too long and complicated for me to explain so I would suggest watching the video instead. The door won't open even when I activate both buttons needed, so I can't get the unique dialogue when finishing a chamber in the wrong timeline. However I thought it could be interesting to see anyways.

There are 3 different dialogues when finishing a chamber in the wrong timeline, this first version is for chambers: 03 04 10 12 14 17 20 22 24

Transcript:
You create your own solution,
which is great!
Technically you were supposed to do something else.
But who cares anyway, keep going.



The second version is for chambers: 05 08 15 18

Transcript:
So, you solved it.
Not in the intended timeline,
but you solved it.
Congratulations!



The third version is for the following chambers: 02 06 09 11 13 16 19 21 23 25

Transcript:
Well, this was not the way this chamber was meant to
be completed.
But good on you for solving it anyways.
Please quickly travel to the other timeline to continue.

Thanks to Jacky720 for further extending the lists of which chambers corresponds to which dialogue.

If you have any other chamber where you have found a way to get a wrong timeline end, feel free to message me or comment here and I will try to put it in this guide.