In the history of personal computers, the first significant home computer was the Altair 8800, which briefly made a cameo on this blog with the game Kadath. Quite soon after — designed originally as a terminal to use the Altair before it became its own project — was the Sol line, which appeared on the July 1976 cover of Popular Electronics and was sold in three ways: in kit form, without expansion slots (Sol-10) and with expansion slots (Sol-20). At the time it was called the first complete small computer; it is now sometimes called the first “modern computer” or first “all-in-one” computer.
It did reasonably well — 10,000 units — but in historical memory it is overshadowed by the Altair and Apple I, and shortly after it landed it got bowled over by the Trinity of 1977 (TRS-80, Apple II, Commodore PET).
At the Smithsonian, from DigiBarn. The Apple I and Altair are on the table above, carefully labeled, while the SOL-20 is hiding underneath on the floor with no label at all. I’m not sure if the curator meant this as a metaphor.
The machine eventually was discontinued in 1979; the designer, Lee Felsenstein, ended up going on to design the first successful portable computer (the Osborne 1) but that’s a story for a different time.
Even when a computer is “discontinued” it still can have fans, and the SOL-20 has its diehards and events, like a 30th anniversary party. One such fan, Ray White, wrote what was more or less a private collection of games, including an RPG called Deathmaze. Skull Cave, his only text adventure (and what appears to be the SOL-20’s only text adventure) he estimates to be from 1982.
The setup has an Infidel vibe (“disease, hunger, monsters and desertion” taking their “toll” on your “hirelings”) but the better comparison is Dungeons and Dragons, especially because the final obstacle feels like a scene from one of the very famous early campaigns.
But also: there’s random enemies seeded around for combat. From the opening room above, you can head south (into the “mouth”) to do combat with a skeleton, or head up (through the “eyes”) to do combat with a goblin.
The author here ran into the same problem many adventure writers were running into: how to make the combat interesting? Adventure and Zork both used it a limited amount, so the encounter with (say) the Troll was colorful and not repetitive. Deadly Dungeon tried to give you arrows for a second method of attack, and Eamon added dynamic movement to the monsters, spells, RPG stats, and the possibility of emergent behavior.
Unfortunately, Skull Cave is just taking its cue from Adventure/Zork. Combat isn’t nearly as interesting as Eamon: the only thing possible to do is to ATTACK when entering a room with a monster and hope you win. You can’t even run away and choose to engage later.
YOU CAN’T JUST LEAVE IN THE MIDDLE OF A FIGHT!!!
Sometimes this sort of game has a “experience path” where if you’ve killed weaker enemies you’ll have an easier time against stronger ones. Unfortunately things are too random for me to be sure if this is true, and I found the best strategy is to attack as minimally as possible, because there’s always a chance of random death. You can spend some points for one reincarnation, but after a second death the game is over.
The game is in two sections. The first spans from the skull cave entrance to a locked gate, with a “Guardian of the Gate” enemy. Other than the initial skeleton-or-goblin fight the next one you have to do for certain is the guardian, and you just need to hope you get lucky and restart if you don’t (the game has no saved game capability, either).
I marked the start room at the top and the gate room at the bottom.
In the middle you can choose to fight a troglodyte and get a jeweled wristband, swipe a number of treasures (silver bars, emerald, painting), smash a statue to take its jeweled “eyes”, swipe a glass bottle and a chain, and battle a dragon (which drops gold if you defeat it).
There’s also a room with a magic word (“PLTMP”) which teleports you there and seems to work every time, being the only escape from combat (too bad I found it last when I was mapping!) There’s also a completely unmappable maze, and I’m not exaggerating “hard and annoying”, I do mean unmappable:
If the author meant to copy the “all different” maze, then separate rooms need separate messages. The item-dropping method doesn’t work; any items just disappear instantly. I think the author may have messed things up from their intent.
Going back to the locked gate, if you defeat the Guardian (again, I just made a beeline and crossed my fingers, no tactics whatsoever) then you still have the locked-ness of the gate to deal with. I had found SEARCH worked from my various tests but mostly it shows nothing. However, if you happen to use it at the skeleton room at the very start, you can find a skeleton key.
This is not a guaranteed search either! Again, I feel like the author might have had D&D in mind, but given SEARCH works almost nowhere, having it also possibly fail the one place it does work is just cruelty.
(The funky error line is because I made a typo and tried to hit BACKSPACE, which doesn’t work on this emulator. I assume SOL-20 had a backspace but I’m not sure how to trigger it.)
The key leads down to a slightly more interesting area.
Yes, slightly more interesting, just the usual Adventure puzzle where the bottle from the north side is useful to pour water on a plant to turn into a beanstalk. There’s also a scene with a “beautiful girl” which gives you a scroll with the spell NIGNOG which seems to be used for defeating one (1) enemy of your choice:
There’s a tiger attached to a pedestal where you can choose to walk away, but once you fight, you’re committed. Defeating the tiger reveals a gem. (I tried NIGNOG here and got no luck, but I think it was because I wasn’t technically fighting the enemy yet.)
With the gem in hand you can go back to reveal a sword stuck in a stone, and use the gem to free it. (MOUNT is a verb I got from the binary code of the game. Unfortunately it is in machine language so I can’t determine a lot of things otherwise.)
Then, with the sword, you can get to the scene which I mentioned reminded me quite directly of D&D.
Specifically, the infamous “Tomb of Horrors”, which originally debuted in 1975 in tournament conditions, then got published in 1978 and has been used by Game Masters to gleefully torture players ever since. It has traps on traps on traps on traps, and a battle with a lich at the end assuming players even get that far (which is just a skull which floats and sucks out one soul per turn).
From a larger piece of art by Jason Thompson describing an actual play session.
I think there might be some more resources, but just NIGNOG (which stuns but doesn’t destroy) plus the sword were enough to destroy the skull. Just NIGNOG alone doesn’t cut it. I assume our player is the “monk” class since they’ve been going without a weapon most of the game taking down skeletons and so forth, but sometimes you need a little magic even when you’ve got fists of fury.
There’s a map up at CASA Solution Archive which includes a place with a “ring” I never got to visit — if you look at the plant room there’s a hook where it seems a chain could go, but I could never find the right verb to make it work — and I also skipped entirely a spider guarding a room with a shield. These tools only came after the majority of combat in the game; Skull Cave really could have used spreading out some of the combat resources in a way that picking them up in the right order could have slowly leveled combat up so the player wouldn’t have to just roll the dice on the guardian or the tiger.
Oh, and I’ve failed to mention the thief. Ugh, yes, there’s a thief.
The thief grabs any treasures you’ve gotten — which seem to be purely for points — and stores them, I presume, in the maze. The problem is the mazes are broken! (In addition to the “all different” maze there’s an “all alike” maze which is equally broken.) So while the source code indicates a “lair” where presumably you can retrieve things…
YOU ARE IN THE THIEF’S LAIR. COMFORTABLE, (BUT CHEAP), FURNITURE LINES THE WALLS. IN THE CENTER OF THIS ROOM YOU SEE A LARGE ROCK.
…there is no plausible way to get there. Perhaps the author has the exact maze steps and if someone really was determined to hack at the binary code they could find out a way too, but as is, the treasure is all a sideshow to the main task of retrieving the pearl anyway.
For now, Skull Cave mainly serves as a warning as to how difficult it is to make combat fun in an adventure game without making any extra systems. The large number of adventures from this era where violence is actually a red herring seems to be linked to the same trouble: there need to be statistics, extra moves, a wealth of items, enemy AI, and so forth, none of which had an easy-to-copy model at the time–
From the printed Tomb of Horrors module.
–excepting Eamon, but if people wanted an Eamon game they just wrote it in that system. And incidentally, for those Eamon fans out there, yes, I might loop back sometime and do more than 2 adventures, even though they really lean much harder on the RPG than the adventure side. The backlog is just so, so long. And speaking of backlog, what I’ll be getting to next is a game which is very large, whose existence is recorded almost nowhere, and has only been available to the public quite recently.
Renga in Blue 
