I was exploring AtariAge and it came to my view the port of Grail of the Gods done by majestyx for the TI99/4A, and went after the original source in Dark BASIC.
After giving it a look I saw it could be ported to Intellivision and of course, IntyBASIC.
IntyBASIC is speedy enough to preserve the original maze generation code.
I had to redesign the status bar, some monster names (no more than 8 letters), the messages (caveat with my grammar! and made a scrolling window of dungeon.
I've used JLP features because the maze is big (20x20) and there is a point-of-vision array taking note of the places you don't "see"
The game essentially is a Rogue-like or mini-RPG, you move using exclusively the disc, get things or descend dungeon moving over them, if you get near a monster the battle will start automatically, the monsters doesn't move, the weapons/armours simply increase your stats, etc, etc.
Anyway make sure you get weapon/armours because your current ones will waste over battles.
P.S: I only have played the first 3 dungeons, so still the Grail of the Gods is to be discovered
P.S.2: Find annex source code so brave souls could try to put graphics, music and sound effects into this game
P.S.3: A brave soul, Kiwi, made pretty cool graphics for the dungeon and monsters in post #10 http://atariage.com/...g/#entry3954578
P.S.4: Mixed Kiwi and carlsson versions and added a nice title letters, also for game over and you win screens. The text version remains in grail.rom and the new version is grail_plus.rom (everything in a single zip file grail_20180206.zip)
P.S.5: Added ARTRAG's nice sound effects. Thanks! Now in zip file grail_20180207.zip
P.S.6: Added Nyuundere's background music and PDF instruction sheet by mthompson. Thanks! also added a proper credit list in title screen also pressing key 0 turns on/off music. Now in zip file grail_20180208.zip
P.S.7: Added footsteps sound effect when exiting dungeon. Added grail graphics by Kiwi (victory screen) and a skeleton for the game over screen. Now in zip file grail_20180209.zip
P.S.8: Added Game Over and Victory music by Nyuundere, BTW the previous version had title music disabled because I was testing sound effects. Now corrected in zip file grail_20180210.zip
(click to animate graphical version)