A game is considered to be "old school" if it borrows heavily from the conventions of IF games from the '70s and '80s, particularly Adventure (William Crowther and Don Woods; c. 1975) and its imitators. In recent years, the term "old school" is sometimes used pejoratively, suggesting that many of the older IF conventions are tiresome or unenjoyable and should be avoided in newer games, especially hunger puzzles and mazes.
Games that seriously challenged old school conventions and established a "new school" of IF include Photopia (Adam Cadre; 1998; Z-code) and Galatea (Emily Short; 2000; Z-code). Works of IF like these aren't considered games in the usual sense. New school works emphasize story over puzzle, enjoy a greater use of NPCs and conversation, and avoid awarding points for scores. Endings in new school works are often not split into winning and losing ones, although some endings may still be considered better than others by the player.
Also noteworthy, the game Savoir-Faire (Emily Short; 2002; Z-code) is a virtual showcase of old school tropes, except they are presented with new twists.