The kinds of characters that can be played at Multiverse Crisis MUSH are legion. This news file covers the advantages that these characters can have, encompassing powers such as telepathy, assets such as money, or ruling an evil empire, or skills such as martial arts or crafting.
0. MUSH Rules supersede the approved text of your +Advantages, as well as your setting's canon. Advantages will be reviewed and modified or removed as Staff deems necessary.
1. Powers from your setting aren't better than anybody else's, and everyone can be defeated using any fighting abilities, even if they're literally an Immortal God. This is CRUCIAL for everyone to have fun with this many different settings interacting. If Darth Vader, Voldemort, Wing Zero, Alucard, and Ranma Saotome fight, it's going to work like a round of Super Smash Brothers. How one character compares to another is defined by their Power Level, and even Cthulhu isn't going to be much stronger than Ryu. As a practical concern, this means that things like One Hit Kills/KOs, Invincibility, Elemental Immunity, etc. don't work against other PCs as much more than having high attack power or durability.
2. Big Versus Small is a problem with a history here. In short, whatever is appropriate in your setting for taking down a tank, or a giant will work on anything like that. For characters like Goku or Superman, this is as simple as punching. But for Wander or Link, that might mean stabbing weak points or chucking bombs at joints. Meanwhile, if you're Solid Snake or Chris Redfield, you're really going to want to grab a missile launcher or grenades. The point here is, don't abuse rule #1 to use a 9mm pistol to take down a main battle tank unless that's something your character is actually capable of.
3. The biggest KABOOM! we want to see on a casual basis is one or two city blocks. Characters MAY have advantages that permit them to destroy more than this. But Angel Arms and Death Stars are cheapened by frequent use, and should be the subject of a plot arc when they come into play. Use of such advantages will be subject to Staff scrutiny. Characters reliant on heavy military hardware get a bit of leeway here, since what allows them to engage other PCs is often incompatible with some other forms of RP due to size constraints.
4. PCs cannot be "Depowered" unless the setting they come from permits this. Superman can be exposed to Kryptonite, and Power Rangers can have morphers stolen, but there's not much you can do to Goku or Link. PCs may consent to be depowered even if they lack a vulnerability, but may not be compelled to surrender their powers or power level as a condition of entering an area or participating in a TP.
5. Persistent effects (such as being turned into stone), are similar to OHKOs in that they don't work as well as might be expected. Consent and/or special circumstances (TPs) are required for long-term/permanent persistent effects. Otherwise, all PCs are assumed to have sufficient resistance to break out sooner or later.
6. Mind Control, Telepathy, or anything like that requires permission from the target PC for it to work. Additionally, due to high drama potential, Staff permission must be given for mind control to persist beyond one scene.
7. Immunities and Invulnerability usually translate to high resistance and durability when it comes to PC interaction. Fire Man can ignore a forest fire, but not a Firebender. Superman can shrug off a goon's bullets, but not Revolver Ocelot's. Flat-immunity is allowed for mind control/telepathy, persistent effects, goons, environmental hazards, and stuns.
8. Characters who have a lot of advantages, like a Wizard with a spellbook, don't have to list them all. This is called an implicit advantage. Some things are NEVER allowed to be implicit advantages: Mind control, teleportation, time travel, immunities, anything to do with souls, etc. In other words, anything that is iffy or restricted needs to be explicitly listed and approved. We're more flexible on less strange or advanced advantages.
9. Time Travel is a restricted power. It may never be an implicit power, and will only be issued to players that Staff trusts. In summary though, Time Travel may not be used to change the past, and may not be used to define the future. Closed Time Loops only.