66		DeadCore (Windows, 2014)
65		Prominence (Windows, 2015)
65		Polarity (Windows, 2014)
65		Valley (Windows, 2016)
65		The Magic Circle (Windows, 2015)
64		404Sight (Windows, 2015)
64		All Fall Down (Windows, 2015)
64		Half-Life 2 (Windows, 2004)
63		Caretaker: Sacrifice (Windows, 2016)
63		Half-Life 2: Episode Two (Windows, 2007)
63		The Chronicles of Riddick: Escape from Butcher Bay (Windows, 2004)
63		Redemption: Saints and Sinners (Windows, 2016)
62		Impulsion (Windows, 2018)
62		Half-Life 2: Episode One (Windows, 2006)
62		Prey (Windows, 2006)
62		Psychonauts in the Rhombus of Ruin (Windows, 2018)
61		Memorabilia: Mia's Mysterious Memory Machine (Windows, 2010)
61		Project Eden (Windows, 2001)
61		Star Trek: Elite Force II (Windows, 2003)
61		Mirror's Edge (Windows, 2009)
60		Mortal Coil: Adrenalin Intelligence (DOS, 1995)
60		Doctor Who: Destiny of the Doctors (Windows, 1997)
60		Eco Phantoms (DOS, 1990)
60		Slamscape (Windows, 1996)
60		Vintergatan: Rädda Jorden! (Windows, 2003)
60		Dark Side (DOS, 1988)
55		Eradicator (Windows, 2014)
54		Magrunner: Dark Pulse (Windows, 2013)
54		No Thing (Windows, 2016)
54		Cyberia (Windows, 2015)
52		Duke Nukem Forever (Windows, 2011)
51		NeonCode (Windows, 2018)
50		Eradicator (DOS, 1996)
50		Alien Odyssey (DOS, 1995)
50		Cyberia (DOS, 1994)
50		Cyberia: Mission Norway (DOS, 1994)
50		Mutan Zone (DOS, 1988)
40		Cyberwar (DOS, 1994)

Notes: Games similar to GlPortal, Games like GlPortal, Windows, Action, Sci-Fi, Futuristic, Platform, Puzzle elements, 1st-person, PC, Game Similarities.