Hl1

Hl1 is not a single, fixed entity; it is an acronym used in several distinct domains. The most widely recognized uses are as shorthand for the video game Half-Life 1, and as a designation for the HL-1 cell line used in cardiac research.

Half-Life 1, released in 1998 by Valve, is a first-person shooter noted for its immersive atmosphere, narrative integration, and pioneering physics-based gameplay. The player character, Gordon Freeman, a physicist, navigates the Black Mesa Research Facility and battles both alien forces and military personnel in a science fiction setting that emphasized narrative and environmental interaction alongside action.

HL-1 is a murine atrial cardiomyocyte cell line derived and established by Claycomb and colleagues at Loyola University Chicago. The line retains several features of adult cardiomyocytes, including spontaneous contraction and expression of cardiac-specific genes. It is used to study cardiac electrophysiology, calcium signaling, and drug responses under controlled in vitro conditions, providing a versatile model for cardiovascular research and pharmacology.