There is clearly a lot of similarity to Portal 2, however the puzzle mechanics of The Entropy Centre help it stand apart from its inspiration. Portal's puzzles seem to focus more on movement and timing while Entropy has far more focus on sequence of events. For each object, you effectively get a 30 second window of time that you can manipulate the object back and forth, and you shouldn't need to get too close to that time limit if you're planning the sequence of moves/stops effectively.
Otherwise, Entropy is a good, but not great game. It has some humor, but nothing too memorable. It has some world-building (the environments are interesting and the notes give you a sense that this was an active centre prior to everything going to ruin) but its still largely empty-feeling. And it has an interesting story, but you need to piece it all together yourself from the notes you read throughout the game. If you don't have the patience to find and read all of the notes, you miss out. And if the ending is what I thought it was? Aria is in an endless loop of rewinding Earth only to see it be destroyed again and resetting and restarting all over again? Basically looping back to the start of the game. That's a refreshing change and very well done.

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!!! THIS LOCIGAL GAME WITH TIME PUZZLES IS REALLY AWESOME !!!
...
...but my brain melted.

P.S. I have to say that the story is even more interesting than in Portal.