Windows XP / Windows 2000
Penumbra is a horror-puzzle game by Frictional Games. Penumbra is a more classic style horror game, where you can fight back, but it is much safer to hide as you try to survive. Weapons, ammunition, and supplies are scarce. The enemies are much stronger than you. These are all reasons Penumbra (and the other recent games by Frictional) are some of the best (and nearly only) recent horror games.
Most other horror games are now really action games, but Penumbra is all about atmosphere and creating a sense of dread. You must navigate an abandoned bunker deep in the Arctic, solving physics puzzles and avoiding enemies. The physics based puzzles give the game a lot of options and they use them very creatively. This variety of puzzles is great and keeps things fresh throughout. The combat is a bit hit or miss, however. You actually have to swing your weapon with a mouse, which can make things exciting and desperate, but the camera can be a pain. The graphics are of a decent quality but are fit the theme very well, being dark and dreary. Everything in Penumbra is designed towards creating the atmosphere of gloom and doom. Penumbra is a great horror game, and you don't see many of those nowadays. So even with its few issues, it is definitely worth a try.