This is such an awesome mod, its great, fun, entertaining and provides an interesting challenge by adding the time travelling portal.

The backstory starts revealing over time, specially near the ending levels, and its such a cool concept, tbh.

While some people say it felt pretty short, i think this actually is quite the right lenght. This is considering the replay value in this game. Because it has an INSANE amount of replay value. There's ways to end the levels on each side of the green portal, either on the future or the past... i ended one of the chambers in the timeline it wasnt intended to be finished, and the game even congratulates you for this and opens a portal for you to switch timelines without needing to re-do the whole test, which means you could very well finish the game using both sides! This adds a whole lot of replay value, specially when it comes to speedrunning and stuff, by making you look for faster strats, now with a 4th dimension to have into account!

The ending is pretty interesting, as it links the lore of this game not only with the portal series but with half life, and it makes sense in a way, so thats a good job and a good way to end the game.

Now, when it comes to the quality of the game itself, we have to talk about multiple points here:
The puzzles are great. They dont really get tedious to deal with, as the 4th dimension element is fun to play with and adds an extra challenge to every chamber. Nothing is made by mistake, its all there for a reason... well except a few cases which i'll point out later.
When it comes to the visual quality of the levels, i have to say that there are many small details that look really neat, specially the fact that they made a new and decayed version of each chamber, adding multiple details of disrepair and the background behind the walls, giving a sense of depth in the world, and that, there is more to be explored behind the testing chambers' walls. From the begining to the end, each level looks good and doesnt have any bad looking aspects to it, all of them feel like they could very well have come out of the base game with the quality they have.
The only part where the quality didnt seem to be as high was during the final cinematic. The lighting in the background elements you see while going up the elevator was kinda weird sometimes, and the ending scene in the outside looks pretty bad, tbh, that part was quite graphically ugly, but the problem was inherent of the plant assets that were used ... could have been fixed if the place didnt look like it was a flat plane world with some trees, by adding a few rocks and terrain deformation, and a bit more plant variety, by scaling up and down some of the trees and maybe adding some bushes to decorate. Another downside of the final cutscene is that the animation seems pretty bad, it has some rough movements but, tbh, thats just an ending cutscene and not everyone knows how to smoothly animate... animation is a tough job. Tbh, the only reason why this animation quality was so noticeable was because the rest of the game had an astonishing level of quality.

Now think about this, the only downside in the whole game is that the final cutscene doesnt look as pretty as the rest of the game... let that sink in, that just proves how good this game was in all of the playeable areas.

Now, lets talk a bit about the bad parts of the level design... the design itself works properly, it does what its meant to do, it looks beautiful, and its well crafted, BUT, there are a few spots where you can very clearly cheese your way out of the chamber without doing what you were meant to... right now, i have no clue what the real answer to the final chamber is, because i just cheese my way out by doing a strafe jump, lol. But being able to cheese levels is not always a bad thing. There's part of the fun, looking for ways to cheese levels and break them, adding even MORE replay value!

All things considered, this mod is AWESOME!

This is such an awesome mod, its great, fun, entertaining and provides an interesting challenge by adding the time travelling portal. The backstory starts revealing over time, specially near the ending levels, and its such a cool concept, tbh. While some people say it felt pretty short, i think this actually is quite the right lenght. This is considering the replay value in this game. Because it has an INSANE amount of replay value. There's ways to end the levels on each side of the green portal, either on the future or the past... i ended one of the chambers in the timeline it wasnt intended to be finished, and the game even congratulates you for this and opens a portal for you to switch timelines without needing to re-do the whole test, which means you could very well finish the game using both sides! This adds a whole lot of replay value, specially when it comes to speedrunning and stuff, by making you look for faster strats, now with a 4th dimension to have into account! The ending is pretty interesting, as it links the lore of this game not only with the portal series but with half life, and it makes sense in a way, so thats a good job and a good way to end the game. Now, when it comes to the quality of the game itself, we have to talk about multiple points here: The puzzles are great. They dont really get tedious to deal with, as the 4th dimension element is fun to play with and adds an extra challenge to every chamber. Nothing is made by mistake, its all there for a reason... well except a few cases which i'll point out later. When it comes to the visual quality of the levels, i have to say that there are many small details that look really neat, specially the fact that they made a new and decayed version of each chamber, adding multiple details of disrepair and the background behind the walls, giving a sense of depth in the world, and that, there is more to be explored behind the testing chambers' walls. From the begining to the end, each level looks good and doesnt have any bad looking aspects to it, all of them feel like they could very well have come out of the base game with the quality they have. The only part where the quality didnt seem to be as high was during the final cinematic. The lighting in the background elements you see while going up the elevator was kinda weird sometimes, and the ending scene in the outside looks pretty bad, tbh, that part was quite graphically ugly, but the problem was inherent of the plant assets that were used ... could have been fixed if the place didnt look like it was a flat plane world with some trees, by adding a few rocks and terrain deformation, and a bit more plant variety, by scaling up and down some of the trees and maybe adding some bushes to decorate. Another downside of the final cutscene is that the animation seems pretty bad, it has some rough movements but, tbh, thats just an ending cutscene and not everyone knows how to smoothly animate... animation is a tough job. Tbh, the only reason why this animation quality was so noticeable was because the rest of the game had an astonishing level of quality. Now think about this, the only downside in the whole game is that the final cutscene doesnt look as pretty as the rest of the game... let that sink in, that just proves how good this game was in all of the playeable areas. Now, lets talk a bit about the bad parts of the level design... the design itself works properly, it does what its meant to do, it looks beautiful, and its well crafted, BUT, there are a few spots where you can very clearly cheese your way out of the chamber without doing what you were meant to... right now, i have no clue what the real answer to the final chamber is, because i just cheese my way out by doing a strafe jump, lol. But being able to cheese levels is not always a bad thing. There's part of the fun, looking for ways to cheese levels and break them, adding even MORE replay value! All things considered, this mod is AWESOME!