Wyrm by Eben Howard
What you think when you first load up this Java game is: Wyrm? I'm not a wyrm, I'm a snake! Indeed this entry does bear more than a passing similarity to the old "what should I code in BASIC" / "what crappy single game should we put on this phone for people" standby.
So you are a snake, sorry, Wyrm and you eat things and you get bigger. Now, you might think that snake, played rogue-style, which is to say: turn-based, would be too easy. Well, the monsters that you have to nom-nom-nomerize to get bigger attack you if are next to them, so it's harder than you might think. Once you get the hang of it though you get to know the patterns of the monsters and can clear the screen quite easily, which results in victoreh! (As pictured, obtained by graspee).
So, it's quite fun, and it definitely has replay value until you clear the screen, but that won't take you many tries, and once you have done it there isn't much to make you want to play it again. The core gameplay mechanic is fun though so it would have been cool if there were more levels with more gameplay elements that were gradually introduced level by level.
Of course the main consideration with this game is: it it really a roguelike? Well, you have procedural generation of a sort: random walls on the screen, and you have combat of a sort, and you have ASCII graphics, so I suppose it is a roguelike. My initial reaction would have been to say that it wasn't a roguelike, but it does tick the boxes.