Yet, Larn can be compiled from the sources here. Extract the archive, then off to the /src directory and as they say sudo make and then sudo make install. Then run the ./larn.sh from directory above.
The compiler may miss the curses.h library, which can be installed with these helpful instructions.
$ sudo apt-get install libncurses5-dev libncursesw5-dev
The Larn version seems to be the real deal content-wise, though it plays slightly different to one I'm used to. Usually the game gives suggestions for descending staircases, entering buildings, opening doors, chests, praying on altars etc, here you have to use keys. I'm not sure if this can be configured from the command line or if it is defined or absent altogether in this source. More crucially, the version seems to be a bit more explicit about certain potion and scroll effects, which may have been silent in other versions.
Sadly I've found the Linux game to halt occasionally with no helpful output as to why. This has happened when dealing damage to a monster or falling into a pit.
Edit: This might be an adaptation of the DOS version of Larn. I'm more familiar with the Atari ST and Macintosh versions.
Some Larn hints for beginners
The game works with the typical hjklyubn direction keys. Use w to wield weapons, W to wear armour, T to take off armor. Comma key picks up objects, d drops them. Use q to quaff potions and r to read scrolls/books. The key c casts spells, which are three-letter combinations. You learn the spells from books. Casting spells reduces your "spell" count, but it will replenish automatically.
(In some versions you also need: E key to enter, < > climb stairs, O open doors/chests.)
|Home, LRS office, DND store, College of Larn, Bank of Larn, Volcano, Dungeon Entrance, Trading Post and DND store.|
From the top world you can enter various places. There are two dungeons, the dungeon proper and the Volcano. Don't enter the Volcano unless you know what you are doing, or have pretty much destroyed the dungeon first.
The very beginning: Sweep clean the first dungeon level before bothering to go down. There are no really dangerous monsters on level 1, just be a bit careful with slow hobgoblins (H) and multiple enemies. Remember, you have the magic missile spell ("mle") from the beginning, but don't trust it to work every time.
Low level characters: Don't open any chests, avoid the altars, don't wash yourselves in a fountain, don't pry off any jewels off thrones and don't open any doors if possible. You'll live longer. Go down only when you are at least level 3. Hopefully you can afford some weapon and armor, too. There you need to start using your "mle" spell actively, because letting the monsters close on you is never very wise.
|Potions (!), Scrolls (?), Chest (C), Altar (A), Statue (&), Jewel (<), Staircase (%), Trap (^)|
Something that can mess your life early on are the potion and scroll effects, which you desperately need but are unknown to you. One viable strategy is to collect as many potions and scrolls as you can, and when you have 3400 gold, buy and read the Scroll of Identity and see what you have.
All rings and magic items carried bring a cumulative effect and work automatically without you having to "wear" them. Energy rings and rings of regeneration are highly desirable, the former brings back spells and the latter returns hit points faster.
Finding every trick for fund-raising and monster-killing is part of the game so I won't tell everything. Let's just say that visibility-enhancements are also desirable whereas powerful long range spells will give an enormous advantage.
And really, never open a door repeatedly without looking what the effect is.
Play Larn online at http://larn.org. My views on the online version and some further gameplay notes here.