Wherein PC also stands for "pure chemistry," if you have any interest in intelligent, spatial puzzle games, Harry Lee and Alan Hazelden's Sokobond is a must-purchase. As the name suggests, it takes a bit from Sokoban-style box-pushing games, but it adds educational and mechanically engaging chemistry elements. You'll need to connect one atom to others to make compounds such as water and amonia, all of which the game tells you about after completing each of its 124 puzzles. They gradually increase in complexity and design, such as splitting or rotating the compounds.

If you need further convincing, check out the pedigree behind the game: Harry Lee (Stickets, Impasse), Alan Hazelden (Dr. Biology's Educational Game, Traal), and music by Ryan Roth (Electronic Super Joy, Starseed Pilgrim), half of which you can enjoy for free, as linked.

Sokobond is compatible with Windows, Mac, and Linux machines and is 15% off until September 3rd, so I'd suggest picking it up before then for $8.50. Sokobond is also criminally still on Steam Greenlight, so why not be the catalyst that makes the game clear the process by voting for it?