I'm continuing to work my way through the 1983 collection known as The Rainbow Book of Adventures, as we find ourselves facing The Door, another BASIC-language contest written by Jean Roseborough for the TRS-80 Color Computer.
Unfortunately, despite its initial resemblance to a standard adventure, The Door is really just a guessing game -- so don't bother with this one, gentle reader. I'm going to jump straight into the...
***** SPOILERS AHEAD! *****
We're initially asked HOW MANY TRIES?, an indirect way of setting the difficulty as the solution is randomized for each run. I'll try 3, prompting a prescient YOU'LL NEVER MAKE IT! response.
There's only one room here, in which YOU ARE STANDING IN FRONT OF A LARGE DOOR. The door is, at least, festooned with possible options -- a door knob, a door knocker, a button, and a bell. I try to backspace at the command prompt so I can take a clean screenshot, and learn that, SORRY, NO MISTAKES ARE ALLOWED IN THIS GAME! So this parser is going to be a bit of a taskmaster, and in short order I've decided to RI-- no, PU... and suddenly A LOUD EXPLOSION IS HEARD and the game is over. I hadn't realized the consequences of failure would be quite so dire!
On my next try, I attempt to TURN KNOB, then KNOCK KNOCKER, and PUSH BUTTON -- leading into my third try. On my fourth, I decide a more generous number of attempts may be in order, and go for 10. Within three tries under this configuration, as luck would have it, I find that RING BELL works, and victory is ours!
Of course, getting the door to open is not the primary objective here -- the author encourages us to find as many of the 44 possibilities as we can, and it seems the successful choice is randomized each time we start. We can't do anything mundane like EXAMINE DOOR to get a clue, and there's no INVentory. Basically, the engine will accept anything we type, and if it matches the randomized solution phrase it has come up with, we win.
The next successful solution I came up with was PUSH DOOR, and after that, figuring out the actual odds of succeeding started to interest me more than the limited gameplay. As it turns out, our odds aren't all that bad on a strictly probabilistic basis -- 1 in 44 -- though as there's no real parser operating here, we're allowed to make blind guesses using words that the game will never, ever recognize, raising the difficulty considerably. I was hoping that the game's randomness would be something more like a game of Mastermind -- some tricky, hard-to-predict-but-solvable combination of moves on the door and its accessories that would reveal something new about the puzzle with each unsuccessful choice. But The Door isn't opening for anything but a single expected phrase, chosen from a set of 44.
Cheating by breaking out and printing the contents of A$(X), at first, then going full-on Twenty One and dumping the successful phrase in the display code on line 5, I learn that some other viable answers are to BREAK DOOR (which I never tried, though I attempted to HIT DOOR and ATTACK DOOR), KNOCK KNOCKER (which I tried many times), GRASP KNOB, BATTER DOOR, RAP KNOCKER, PROD BUTTON, and THUMP KNOCKER. And while the code checks for some of the traditional Anglo-Saxon curse words and duly admonishes the player with a NOW, NOW, LET'S NOT GET NASTY, it happily allows us to JERK KNOB and LIFT KNOCKER. Less predictably, we can also CRY, CLAP HANDS, SCREAM, and WHISPER PASSWORD.
Unfortunately, it's not much fun to come up with any of these solutions, because the path to victory remains largely random -- even when we've discovered a solution that can work, its actual success is determined by chance, and unlikely to be the pre-selected answer next time around. This tends to undermine the learning-by-experience vibe that makes most adventure games entertaining -- here, even if the player eventually discovers, say, ten workable phrases, the odds of one of them being usable in any given run, and hence the odds of the game being winnable at all, remain below 25%. If we have the source code handy, then sure, 44 moves is always enough to arrive at the right solution. But it never feels much like adventuring, and so The Door ends up being nothing more than a 44-sided die roll dressed up with a cardboard Dungeon Master.