X-Men: Madness in Murderworld is a wonderful action-adventure game placed in Arcade's own amusement park, called, as you might've guessed already, Murderworld.
Professor X (Charles Xavier) has been kidnapped by Arcade and Magneto. You need to save him by finding scattered pieces of the device capable of stopping the villains. It's pretty much normal for a story taken from the Marvel universe.
Most of the game is maze-like and generally a royal pain to get around. Different enemies are nice, with the occasional boss that dies in less than a minute. The player gets six characters, whom are Wolverine, Nightcrawler, Cyclops, Colossus, Storm, and Dazzler. There is also the ability to pick up and use items, which is what gives the game its adventure-like qualities. Puzzles mostly consist of finding a certain key, then opening a lock; of course, only if Wolverine or Colossus can't rip it open. There are also traps, which consist of either things shooting up/falling on the player, or the player falling down several screens. There are also health potions in the game, which are very useful for keeping your X-Men alive longer. Some of the items which you need to win the game are located in something destroyable, so think twice before destroying objects.
The graphics are mostly average, although the different areas are nicely varied.
Sounds are a bit annoying, but still better than some others I've heard.
Start the game using xmenfix.com, instead of xmen.com.