Pleurghburg: Dark Ages

Pleurghburg - Dark Ages is a freeware Adventure Game released by Gaspop Software. It can be downloaded from here

A semi-sequel to the company's earlier non-Adventure game Cops & Killers, the player controls police detective Jake McUrk in the now relatively crime-free city of Pleurghburg. While investigating screams coming from the old morgue he discovers a series of grisly murders perpetrated by a group of robed men. The game plays out over four days as Jake tries to discover the secret behind the robed men before Pleurghburg becomes a crime-ridden hellhole again.

Pleurghburg provides examples of:

 * Black Best Friend: Lucas.
 * Gadgeteer Genius: Lucas, whose inventions will be often useful to Jake.
 * Gorn: Despite the game's ugly graphics, the murders are really grisly both in depictions and descriptions. Unsurprisingly, there's an option to turn off the most violent scenes.
 * Guide Dang It: There's no shortage of Moon Logic puzzles in this game. One of the more heinous examples is
 * Leave No Witnesses: The culprits do this to try and cover their tracks, to the point of killing even people who may have heard just a suspicious noise. A later scene in the game has Jake.
 * Multiple Endings: There's four of them. They depend only on actions performed during the last part of the game, although for two you must also have a particular object from early in the game.
 * Product Placement: The prequel game, Cops & Killers, is Jake's favorite game and a poster for it hangs above his computer.
 * Religion of Evil: What the enemy is revealed to be. No specific explanation is made of their origin, or more specific motives.
 * Unwinnable By Mistake: If, when investigating the site where a van crashed, you don't take the pipe under the van, after leaving the location won't be accessible again and you'll be without an object that's essential later.
 * Wretched Hive: Pleughburg in the backstory. A few years earlier, the city was falling in an unprecedented spiral of violence and corruption, leading to a revolt of the citizens (Jake McUrk was a hero of that crisis). The old police system was removed in favor of the Police Detective Agency and Pleughburg has gotten much better since. Now, the murders Jake's investigating risk bringing terror in the city again.