Culture theme

The ending leaves open some issues, hints on others or otherwise gives similar message.

Batman: Arkham Asylum (Windows)
WIN 2009-09-15
Dead Meets Lead (Windows)
WIN 2011-05-03
F.E.A.R. (Windows)
WIN 2005-10-18
Rage (Xbox 360)
X360 2011-10
Mini Ninjas (Wii)
WII 2009-09-08
Rage (PlayStation 3)
PS3 2011-10
Prince of Persia (Windows)
WIN 2008-12-09
System Shock 2 (Windows)
WIN 1999-08-11
Alien: Isolation (Windows)
WIN 2014-10-06
SOMA (Windows)
WIN 2015-09-22
F.E.A.R. 2: Project Origin (Windows)
WIN 2009-02-10
Legendary (PlayStation 3)
PS3 2008-11-07

The first video game about Open-ended was released in 1991.

Electronic Arts, Bethesda Softworks and Sega has published most of these games

Generally this should only include cases where the open issues are mentioned, hinted at or such in the ending or near it but not by introducing new or returning challenges as per sequel hook. Less so for cases where the earlier story would imply such for those paying attention. Comparable to a cliffhanger without the drama.

Often this is a signal that the game makers want to make a sequel or their desire to feed any fan community they hope the game gets.

The usual mention that it wasn't the last of the protagonist's adventures or something is another story altogether should be ignored as they're unnecessarily common and vague (perhaps add more specific tag for such?).