We’ve seen some rare computers here before — mostly notably a fair number of titles for the Ohio Scientific line of computers, thanks to Aardvark — but we have yet to encounter the Tangerine Microtan 65, a system originating from the UK in October of 1979. For any fans of the system who might be scouring the Internet for information, I am sad to say this will be a short visit; there are only seven adventure games (sort of eight) that I know of, and four are currently lost to the winds of digital time. (The system was followed by the much more famous Oric-1, and Casa Solution Archive has over 100 adventures linked to it, so the company will be sticking around, at least.)

While it was possible to buy an “assembled” Microtan 65, the most common form seems to be the “kit” form with just a board and the hex pad shown here (instead of a keyboard). Image from Tansoft Gazette 7.
Just to lay them out, four of the adventure games are mentioned in the Tansoft Gazette #5:

From microtan.UKPC.net.
We know from different sources that The Sceptre of Hamloth is #1, The 6 Keys of Tangrin is #2, The Tanland Adventures is #3, and ???? is #4. Adventure #2 is available since the source code was in Tansoft Gazette, issue 1; I’ll be playing that game next (it has an interesting experimental game mechanic). #3 and #4 might be on a dusty tape somewhere, they might be in oblivion. Since #4 is in BASIC the source code may be printed somewhere, and there may even be a known port for another system.
The Tangerine User Group newsletter mentions two more; here’s a clip from issue #17 (these didn’t start showing up in the newsletter until issue #16 in 1982):
House of Death is in Issue #37 and is by A. J. Shepherd, aka The Doppel-Ganger; I don’t know about Hoardes of Chaos. There’s also an ad for Viking Raider in a different issue, but since it’s both for Microtan 65 and Oric-1, I’ll be playing the latter version when I finally get to it in 1983.

TUG News Issue 36.
The sort-of-adventure is a port of the Royal Puzzle from Zork III with BASIC source in an issue of Microtan World; there’s no adventure framework at all so it essentially is a pure puzzle game.
…
The Sceptre of Hamloth, credited to an I. Dickinson, joins the only-8K-of-space club (actually 7K here) including ADV.CAVES, It Takes a Thief, and the early Aardvark games. Just like most of those, it’s pretty short on the verbs; it’s a collect-the-treasure-plot where the majority of the game is moving around, picking up stuff, and trying to finish before lamp light runs out.
The map is relatively substantial, but since making the map is almost the entire game, there is, sadly, the usual tendency to obfuscate exits (*); having, say, east from one room link to north in another. On the positive end: There is technically a “maze” but it’s only two rooms.
There is one puzzle — a vampire that approaches and kills the player if you don’t run away.
This is combined with the obfuscated exits; you go EAST to enter the vampire’s chamber, but SOUTH to get back out; trying to go WEST kills you.
Wrong way! He caught you! Everything is fading into darkness…
There’s a “dusty vase” elsewhere; if you BREAK it you can get a crucifix, which lets you get by. (More on this in a moment, though.)
Three other wrinkles. First, the addition of a SEARCH command. I admit I only discovered late that the verb worked. There’s a trapdoor not mentioned in the room description that SEARCH reveals.
You are in a tiny chamber with marble walls. A narrow corridor leads north and a twisting passage leads east.
SEARCH
You have found a trapdoor in the ceiling
This led to some silver coins, but I had found them already by being thorough and testing exits even if they weren’t in the room description.
Second, the titular Sceptre of Hamloth itself. (Presumably, there’s some manner of instructions giving a backstory, but those are also lost to the digital winds.) It’s easy to clear out the ruins and miss the sceptre, as I did the first time around. I suspected I was lacking something and poked around, using my experience with Dragon-Quest Adventure where I missed a similar exit:
(It didn’t help that GO STREAM and CROSS STREAM don’t work.)
I still didn’t have a BIG WINNER IS YOU message after I collected all the items at the starting location. Now, we get to that third wrinkle.
You see, you don’t have to break the vase.
EMPTY VASE
OK
Something fell to the floor
This gets the crucifix as easily as breaking the vase does, and the vase counts as a treasure. I admit I was sidetracked by the vase being “dusty” and trying to clean it (CLEAN isn’t recognized as a verb), but I also could swear I attempted to empty the vase by conventional means before breaking it.
(*) OK, so you’ve got a game almost entirely composed of navigation, and don’t even have a plot really: how do you make it interesting? Other than some pretty environments, the only thing that can be pulled off in this era is a bit of navigation trouble. (**) So I find the slightly askew directions a little more forgivable here than elsewhere. I’d still call it a case of trying to mimic mainframe Adventure on a platform not intended for it; something has to go, whether it be descriptions (making things Scott-Adams-minimalist) and/or rooms (aiming for a tighter experience). A common trope in speaking of art is that technical restrictions give birth to creativity, but The Sceptre of Hamloth is what happens when an author is more stubborn and doesn’t adapt to the bounds of the medium.

Apologies for the mess: I went old-school.
(**) Except… well, you’ll see. Stay tuned for Microtan 65 Adventure #2.
Interesting stuff. I’ve added details about the first three games in the series to CASA in the past but, yeah, I wasn’t able to track down any information about the fourth game. I think at the time I was more concerned with tracing back early British games and, as these were 1981 and I’d started to find games from 1980 elsewhere, I didn’t continue the research much further.
Thanks for the new potential games to add to the database… I was aware of House of Death, but only for the Oric; so I’ll follow your links for a possible Microtan version… presumably, as a BASIC game, the Oric version was derived from the Microtan one.
Viking Raider isn’t in our system at all or Hoards of Chaos.
Actually, the House of Death with have for the Oric is listed from a different author than you mentioned so perhaps it’s not the same as the Microtan game.