From text parser to point and click

The difference between the two eras of adventure games is not graphics. It is what the game expects you to type.

The parser era

The genre begins in text. Colossal Cave Adventure, written by Will Crowther and expanded by Don Woods, is identified by Rick Adams as the first adventure game, and reached players in the mid-1970s. You moved and acted by typing commands: directions, verbs, and the names of objects.

The parser — the part that reads your sentence and decides what you meant — was the interface. Its quality decided whether the game felt fair. A parser with a small vocabulary would reject sensible attempts; a generous one would accept a phrase the designer had anticipated. This is why long-term players of the era talk about the vocabulary of a game the way modern players talk about its controls.

The commercial peak of the text approach came with the parser-driven games of the early 1980s, and the form later returned as a niche with interactive fiction. But as a mass-market format, the verb list lost ground.

What the graphic adventure changed

Graphic adventure games added a picture of the scene and kept typing, at first. The important step is the shift from typing to selecting: the player picks from a list of verbs and clicks a place on the image.

The point-and-click interface reduces the input space. You no longer have to guess whether the game understands “look under the mat”; you click the mat with the “look” or “open” verb selected. Two consequences follow, and they pull in opposite directions.

Good: the interface stops being a puzzle. The puzzle becomes the thing the designer intended — what to do, not how to phrase it.

Bad: the designer’s assumptions become invisible. In a parser game, an unaccepted sentence tells you the idea is wrong. In a point-and-click game, clicking forty hotspots that do nothing can be indistinguishable from a wrong idea, because the interface has no way to say “I understood you, that just is not it”.

The pinned example

The clearest single reference point is Maniac Mansion, which replaced the typed parser with a selectable verb interface built around clicking, and which is routinely described as a landmark in the move away from text input. Its design — multiple characters, several solutions, a house you explore room by room — also demonstrates the format the genre would use for the next decade.

What was actually lost

Two things.

First, expressiveness. A parser can be asked anything. A verb list can only be asked what it contains. The genre traded breadth of input for reliability of input, and the trade favoured reach.

Second, the possibility of a wrong but interesting answer. Typing something strange and getting a written response was part of the charm of text games, and the obligation to respond to arbitrary input disappeared with the verb list.

Why this still matters when playing today

Because it tells you what a game is asking of you. In a parser game, your problem is finding the right words; the game is a language puzzle as much as a spatial one. In a point-and-click game, your problem is finding the right interaction; the game is a set of state changes you must discover.

Knowing which one you are in changes how you take notes, and how quickly you conclude you are stuck.

Sources

• The Interactive Fiction Archive — the parser-era interactive fiction that the text format became after its commercial peak.
• SCUMMVM — compatibility list — point-and-click and graphic adventure titles, the on-screen verb interface replacing typed input.
• SCUMMVM — supported games list — Maniac Mansion and the selectable-verb interface it introduced.