The odd genre marketed as "adventure" computer games began with text parser input and the promise of interacting with a virtual environment or situation through the use of natural language. "Natural language" here meaning "brutal cave-man imperatives." OPEN DRAWER. GET KEY. GO DOOR. GET KNIFE. These are sentences or fragments frequently stripped of "noise" unnecessary for communicating intent to the machine: articles, prepositions, etc. This doesn't just reduce the amount of text input required by the player, it makes it easier to identify syntax problems. If you want to GET the KNIFE and you know the machine recognizes the meaning of "GET," an error could mean that the machine will recognize only the object's full name: SHARP KNIFE.
Maniac Mansion typifies a kind of graphical adventure game that dispenses with the pretense of natural language altogether and distills the brutal cave-man imperatives into a curated verb list.
We're not pretending I can apply every conceivable English verb to this situation. I can PUSH, PULL, OPEN, CLOSE, GET, USE, READ, GIVE, GO TO, TURN ON, or TURN OFF things. That these were specifically chosen from countless other verbs lends them significance or credibility. I'm not wondering what range of interactions could be possible in Green Tentacle's room. I'm wondering what will happen when I PUSH, PULL, OPEN, CLOSE, GET, USE, READ, GIVE, GO TO, TURN ON, or TURN OFF its different elements.
The spaces in this game are depicted with uniform scale and perspective on a shallow proscenium inside the black border that houses the interface and the dialog bar. You can see the wiry lines that separate the floors from the walls from the ceilings. It's a kind of modular template into which doors and objects have been stamped--a pristine world in miniature, like a doll house. This is also noise reduction. The dense accumulation of dirt and objects that would actually litter an environment like this have been omitted. Any game environment is blatantly artificial, but the sparseness and uniformity of these rooms betrays the way in which they were designed and constructed. It makes plain to the player that each element has been deliberately placed. Every object is equally suspected of concealing some transformation to witness or secret to unlock. The mind buzzes with possibilities. What happens if I PULL one of those giant speakers up in Green Tentacle's room? Is there something behind it? Will it tip over? Well, no. You can't PULL the speaker or any other object in the room because it's not one of the few interactions that was assigned a unique response. (There's actually no way to interact with the speakers at all, beyond reading their description.) You can't PULL the poster off the wall or the stereo off the shelf. You can't PULL Tentacle himself. PULL winds up being a funny verb--like PUSH, TURN ON, and TURN OFF--that applies only to a handful of situations where the generic interaction of USING something was deemed "too vague." You can't USE a bush to rip it out of the ground, but you can PULL it. For some reason, OPENING it also works. There's a lot of overlap, which is an attempt to broadly accommodate player intent and save them the effort of figuring out how to express what they want to do once they've figured out they want to do it--but this was a large part of the intent behind creating this list of mostly superfluous verbs, rather than incorporating a parser, in the first place.
By the mid-90s, these games generally began folding all of the intended nuance of PUSHING, PULLING, OPENING, CLOSING, GETTING, USING, READING, GIVING, TURNING ON, or TURNING OFF objects into a handful of super commands. USE or "generic interaction" usually means "do some unspecified, context-sensitive thing to something in the environment." It opens doors. It turns on appliances. It can knock things off shelves for you. READ gets folded into "LOOK." LOOK at something with text on it to read the text. GET might still be its own verb, for collecting objects, or it might also be folded into USE. Cyan's Myst (and many of the endless Myst-likes) uses one generic "interact" command for everything. Click to move forward, click to read the note, click to collect the object, click to pull the lever on the machine you're figuring out. That works for Myst and other games with sterile, empty worlds. They're not about characters. They're about the environments. Moving through the environments. Observing the environments. Manipulating the environments. Hence the focus on the tactile business of fixing broken-down machines all the time--the adherence to a mildly magical realism in the setting demands that objects adhere to a fictive logic. It's a lot easier to design alien, artificial/mechanical constructs that behave in a complex and passably logical way than it is to handle the natural world. Imagine Myst, same game, no machines, everything you interact with is a plant or a rock or an animal. Complex deer-feeding puzzles. You fucked up. The deer are unhappy. Now they ran away. Oh boy, the deer came back. Time to try the deer puzzle again.
Games in the tradition of Maniac Mansion lean far more heavily on characters and personalities. Those are the selling points: the writing, (and later, the voice acting,) the jokes (if any,) the drama (if any.) If there are only three verbs, two verbs, one verb, it's hard to create the illusion that the player is embodying a character. It ceases to feel like decisions are being made, starts to feel like hotspot hunting to trigger cutscenes--which, in those cases, it usually is. This is what the inventory has come to be used for. The parser and the array of general-purpose verbs were jettisoned. Every inventory item is a verb, typically capable of enabling one action in one area before vanishing, having served its purpose. Sometimes you can use them for more than one thing. This is why these games tended to get progressively "wackier" or more esoteric inventory items--because the sequences triggered by using them are usually the ones where central characters are capable of affecting the greatest degree of change in their fictive worlds. The item, the instrument of this, has to bear the weight of the personality the player otherwise lacks the tools or commands to express. Use item A on character B. Watch cutscene. Get item C. Walk to next room. Walk to next room. Combine item C with item D to create item E. Use item E on object F. Watch cutscene. This is a script on a drip feed. Your Rubber Chicken and your Crowbar and your Can Opener are keys that unlock doors within this prison world. The doors only lead to more rooms within the prison.
You can see the seeds for that in Maniac Mansion, see how the "genre" arrived there from here, but Maniac Mansion was made before this establishment of an unspoken consensus that player agency couldn't be allowed to upset the puzzle chain or the static characters and events within. It has unpredictable reactive and multi-linear elements that were abandoned by nearly everyone working within the "genre" in subsequent years. It opens with a choice--pick two of six kids to complete your "adventuring party." The kids' abilities differ, to a degree. The kids react differently to situations, to a degree. Cowardly nerd Bernard runs when a monster appears. Amoral nihilists (musicians) Razor and Syd are the only ones willing to microwave Weird Ed's pet hamster. Only Wendy can rewrite the villain's terrible memoir and end the game by procuring for him a publisher and instant celebrity. Only Michael can develop Weird Ed's microfilm, earning his assistance in entering the game's final area. Get Green Tentacle a record contract and he'll offer similar assistance. Show him your own record contract and he'll kill you. Show Weird Ed his exploded hamster and he'll kill you. Microwave radioactive water from the pool and the steam kills you. Drain the pool to expose the nuclear fuel rods within, causing a meltdown and killing everyone. Ultimately dispatch the villain by getting him that book deal, calling the space cops on him, launching him off the planet in a rocket-powered car, or feeding him to a giant carnivorous plant. There's a special ending for killing all your characters. The happier endings are modified to acknowledge playthroughs that resulted in the deaths of one or two of the three.
All the business with record and book deals is handled through a dude at one agency. He has unique reactions for almost all of the objects you can send him--only two of which result in anything happening that helps at all with "finishing" the game:
That all these reactions were implemented exemplifies something about this game: it's small, it's old, it has an interface that wasn't fully exploited. It's still more open, more interested in reacting the to the player's prodding than most other games I've seen in this vein--even very recent ones. What's the story in Maniac Mansion? Given the random character combinations, the branching paths, the multiple endings (successes and failures,) how do you summarize it? How many other games of this type can you easily distill into a narrative based on the fixed and linear chain of events that inevitably must occur? Maniac Mansion describes instead a general situation populated by entities who might or might not collide in various ways according to the characters chosen to feature and the player's whim in applying their abilities. All of the accumulated variations on and outcomes of of the rescue mission are the "story." I see ideas like this in "role playing games" that justify this degree of agency or this interest in multi-linear situations through the rigorous application of statistical checks to measure whether a character has earned the right to do what the player wants--a different set of keys for a different set of locks. Maniac Mansion has locks to be opened, but those primarily are bookends to a brief but interesting period in which you can ditch the official business of settling the plot and scrape around to discover the surprising hidden details. There's a seed in there for a different idea: an interactive situation focused on the goal of thoroughly exploring the various outcomes found by applying a limited range of commands to a limited environment.
EDIT: 12/2/2011: COOL COMMENTS BELOW \/\/\/\/\/\/\/\/