1711, from episode + -ic. Episodical is from 1660s.

occurring sporadically or irregularly.

Occurring in a long string of short, individual scenes, stories, or sections, rather than focusing on the sustained development of a single plot. These episodes may be unrelated to each other directly [..]

a film that is composed of a series of loosely-related segments, sections, or episodes, with the same character(s) Examples: Intolerance (1916), Around the World in 80 Days (1956), Short Cuts (1993), [..]

A literary work consisting of a number of more or less self-contained but loosely connected incidents (episodes) strung together by the author to form a narrative (example: Idylls of the King by Alfre [..]

(adj) of writing or narration; divided into or composed of episodes(adj) occurring or appearing at usually irregular intervals(adj) limited in duration to a single episode

With the exception of Telltale games and very few others, a guarantee that the game you just bought will never be finished and you should not get too attached to anyone.