Just buy it.

[PicAxeAndChill]

It was a steal on day one. Don't look up any walkthroughs and you'll be in for a load of fun that you probably haven't had since Portal/Portal 2. Wait a few months and you'll probably be able to replay it without remembering the solutions.

[Californ1a]

Even if you are the type who cares about reply value (sudden replay value), then you can always try your hand at speedrunning it.