Half-Life 2: Short Stories is a team working on a group of modifications that take place in the same realm. A lot of the focus is on the story and gameplay, new innovative set pieces and puzzles. After the release of the first episode of Human Error, the team is planning to release more episodes and expand the characters and the world.
This review may contain spoilers
Few mods pull of what this mod does. I have yet to play a mod that has combine gameplay better than this one. I love the section where you get to use the APC. Not to mention the multiplayer, which has new and original game modes. On top of gameplay I enjoyed the story. Though a few of the characters were less that pretty, it didn't really bother me all that much. It was also fun to get to see some enemies from Half-Life 1 reiterated in the source engine.