Cave Noire

Original Title
Game Boy
Official Website
Konami's Cave Noire saw release in April 1991 and predates other console/handheld Roguelikes by a clear two years - Torneko's Daibouken didn't appear on the SFC until 1993 and the first Shiren came out in 1995. As both the first and then only attempt in the genre it takes a relatively unique "bite-sized" approach to dungeon exploring.
There are four quests for you to freely choose from, each with a different goal and different challenges. The first is straight up monster bashing; you must defeat a minimum amount of monsters and then escape through an exit door. The second is coin collecting; coins are either in plain sight or collected from treasure chests or enemies, with some being worth more than others. Then there's orb collecting – this one presents a new challenge as orbs must be carried as part of your equipment, meaning each orb you pick up is one less free slot for potions or spells. The final quest has you freeing fairies from cages; first you must locate a key (and there is not necessarily one on each floor) and then find the imprisoned fairy and free her.
Each quest completed gives access to a harder difficulty level, going from 1-9 and finishing with "M" difficulty. Not only does this mean you need to collect more coins or kill more monsters to complete your task, but the game will also place tougher enemies and new items within the randomised dungeons. Dungeon layouts may be completely random, but the rooms are not. However this doesn't mean the game is predictable; rooms can be flipped, contain completely different enemies and treasures or even have secret exits that weren't there before (marked by a "?" over your characters head).
Your characters stats (you are free to choose and rename a male or female adventurer) are based on the difficulty level and are fixed. Certain items can give a temporary boost to these stats while you are within the dungeon but these benefits don't carry over to your next attempt whether you are successful or not.
They key to Cave Noire is understanding monster behaviour. Each monster has very specific movement patterns and attacks, and knowing how to avoid them is often the key to surviving. One enemy is completely passive and will not attack at all, others will actively seek you out and sometimes even the biggest monsters will only patrol in one spot and not attack unless you get too close.
Throughout the quests you will pick up items, some are simply hurt/heal potions or spells that can cure wounds or set enemies ablaze, but others are more subtle – the ability to summon a rock might not seem useful, but careful placement can save you from running into a dangerous enemy.
Cave Noire appears to be Konami's only entry into the roguelike genre, and has received no sequels or remakes.
A translation patch is now available here.