noun
game cartridge; game cassette
Refers to a physical cartridge containing a video game, used with older consoles. The term カセット alone can also mean 'cassette' in other contexts.
See also: カセット
ファミコンのゲームカセットを集めている。
I collect Famicom game cartridges.
カセット is a broader term for 'cassette' (audio, video, etc.), while ゲームカセット specifically means a game cartridge.
Loanword from English 'game cassette' or 'game cartridge', adapted into katakana.