Treasures of a Slaver's Kingdom is a text adventure of sorts by S. John Ross. It's likely to offend the sensibilities of Real Interactive Fiction lovers, as it pares down input to a handful of commands. I love this because I hate “guess the verb” gameplay. Treasures also features simple stats-'n'-dice-based combat, which puts some people off. On the positive side, it's a giddy pulp pastiche of Conan, Star Wars, and more. Atomic dinosaur? Sure! Give him a light saber! The writing is frequently hilarious. The game is solidly designed: the environment is fairly small, the inventory is kept to a manageable size at all times, and you can't really get stuck.
I discovered the game through Emily Short's excellent (as always) review over at Play This Thing. I really can't add much to her review, so head over there to read it.
Treasures does a good job of making memorable non-player characters. You actually feel like you've got a relationship with them. I think the limited input vocabulary helps here as it keeps you from getting frustrated trying to interact with them.
The full game costs $13, which I think might be slightly much for the amount of gameplay. I got through the game in under eight hours, although I made fairly extensive use of the crypto-clues offered in the instruction manual, to the point of writing a Python script to decode them for me. However, I spent the entire time playing the game with a big grin plastered on my face and laughed out loud on several occasions.
There's a free demo that lets you play the first fifth or so of the game. Try it out and see if it agrees with you. You will also need a Z-machine interpreter to run the game; Gargoyle is a very nice-looking one.