The Looker

Here is an excerpt from The Looker's Steam description:

Explore several charmed locations on a mysterious island replete with over 55 creative puzzles. Over an approximately two-hour playing duration, you will face unique challenges, ponderous ideas, and feebly amusing in-jokes.

The Looker is a single-player game that respects you as an intelligent player, and it treats your time as... reasonably valuable (I mean, don't let me pull you off solving the Riemann hypothesis or anything). As such, I will level with you here—not every joke will be a hit, but there is no filler material, the puzzles are fun, and, if you really think about it, aren't the real solutions the, uhh... friends we make along the way?