When you’re first acquainted with Twilight Heroes, it may seem a bit...well, average. In all respects, it looks a bit like a low-fi ripoff of Kingdom of Loathing. After a little while with the game, though, you learn that this isn’t true at all.
The basic structure is the same. You use up adventures/turns in different areas, fighting monsters with neat pictures and funny text. The similarities stop there, though. Twilight Heroes has a much darker and more serious feel to it; there are still jokes, of course, but your avatar and his enemies take themselves much more seriously-which isn’t a bad thing. The art is different, too; instead of relying of simple art to convey things, Ryme, the creator and admin of the game, takes ordinary photos and warps them in Photoshop, creating images that can, at times, be downright creepy.
The underlying mechanics are much different, too. There is no food or booze system in this game; instead there’s only Coffee, which has a much smaller role in the game. Another neat mechanic is the “time” system. Every adventure is assigned a period of time; generally it’s five minutes, but certain activities may use up more of that. You can’t adventure past your bedtime, but you can extend your bedtime by various means (such as, again, caffeine). There’s also a hard cap: At seven AM, you can no longer adventure. You have to go to work, after all. In addition, you can, over the course of the game, decrease the duration of various activities (one item you get makes it so all adventures take 4.5 minutes instead of 5). This allows you to use more turns before you need to go to bed/work.
The content, on the other hand, is just as solid as the mechanics. Places such as the Renegade Robot Hive, the Zion Tears Building, and the Retro Rave are all memorable.
Twilight Heroes has recently gone from Alpha to an open Beta. As such, the game is still very much a work in progress. Since many of the Alpha testers were also Kingdom of Loathing players, when the game was opened up to the public, a huge influx of new players joined. As such, the site’s been crippled with terrible lag and 500 Errors. Ryme is doing his best to acquire new hosting, though, and this issue should be fixed soon.
Twilight Heroes is an interesting game, and it’ll be interesting to see how it evolves. It’s also very fun.
Update - 1-2-2008: The lag and 500 issues were fixed a while ago, and new content is being introduced on a regular basis. Twilight Heroes is a great game, and it's improving steadily.
Full Disclosure: I am a moderator for Twilight Heroes.