This is level 2 of the Memory Evaluation.
Note: Since you can only use the Gentleman in this tunnel, he will be the only recommended character.
In this level, you still don't really need to memorize the route, since it can be followed easily. First, take a right turn, then turn slightly to the left. Do a jump to the right, and you will pass the first half of the level.
Do this order again in the next half. The route is identical. If you really can't do this, you can try and look for the outline of the Power tiles through the absence of the background stars.
After this level, a cutscene will be initiated.
There is a cutscene that featured in this level. More information about cutscenes can be seen in this page.
After beating the Memory Evaluation, part 2, a cutscene featuring the Gentleman begins. The Gentleman notes that the simple design of the tunnel makes it too easy to complete. He then leaves and comes back with a ring, which he uses to move the tiles around into a more presentable structure. Pleased with his changes, the Gentleman continues on to revise the dark area in the tunnel to match the earlier part. Afterwards, he comments about how easy it was moving around in the dark area, "at least for one with his mnemonic prowess". The Gentleman thinks out loud that he should really hire others to do this work, saying that he should not be required to perform such mental labor himself. He continues walking through the tunnel only to step off a dark tile and fall, displaying just how good his memory skills are, indeed.