AL TIER SCALE--
Level 1 || This is the general human level, encompassing the power attainable by the average Joe and is limited to the most basic of technological weapons, like guns, crossbow and knives—maybe even a scooter if in the wrong hands.
Level 2|| Human abilities at their peak, but still nothing overtly supernatural. Examples would be a genius IQ, very minor spell-casting ability (I’m talking sparking dried brush into flame). Technological objects such as laser guns fall under this level.
Level 3|| Genetic, cybernetic, divine or magical enhancements that allow you to run as fast as a sports car, jump anime style, or bench three-hundred pounds without breaking a sweat—as well as other physical modifications of that level. Dexterity level equal to an expert marksman, low level psionics and spellcasting ability, super-genius intelligence quotient and martial arts master are other examples of Level 3 abilities. Equipment falls under the same range of power.
Level 4 || Examples of Level 4 powers and abilities include Mad Scientist level genius and scientific ability, long ranged telepathy, magical powers that to not involve a divine patron, and the ability to shoot flaming bats with magic arrows of light without the aide of that damnable fairy partner. In general, the range of ability to be expected from a Jedi Padawan of Star Wars or a Gennin Ninja of Naruto—as well as the use of cybernetics, alchemy, and so on to simulate any of that.
Level 5 || The basics of nano technology capable of regenerating minor wounds, or alternatively wizardry or clerical ability capable of the same. You can pilot your own short range star fighter and have access to technology so advanced as to be almost magical in nature. The ability to fly for any reason you can think of that makes any rudimentary amount of plot logic. Your character may have the reflexes and skills of an elite Jedi Knight, the speed of Saito Hajime, and the power to take down Trinity of The Matrix with ease.
Level 6 || The ability to heal major damage taken bother personally, or by others, through the method of your choice. The charisma and influence necessary to muster an army of elite soldiers, and access to the technology needed to build and operate a small space craft capable of interstellar travel (or a magic dragon from the future, whatever floats your boat). Your powers and skills rival those of Gandalf the White, Obi-Wan Kenobi and Himura Kenshin at their best.
Level 7 || Personal shielding and an Imperial Star Destroyer for a flagship; computer expertise that can take down Borg Cubes, and you may have weapons so slick and high tech that they make the ladies hot and bothered. You can distort space-time at will with your magic, enough so to influence events worlds or even years away, and your physical strikes can no longer even be seen. Armies of grizzled veterans--wearing too much steel to stand up on their own—will carry your banner to war and ride really expensive looking horses across the battlefield. You could out gun an Agent in the Matrix or beat him down with your martial arts, and powers and abilities compare to Mace Windu of Star Wars, Ultimecia Final Fantasy, and Hyuuga Ricdeau of Xenogears.
Level 8 || The firewalls of the Death Star and Magi Supercomputers fall with ease before your unbeatable hacking skills. You can repair lost limbs and destroyed vital functions expediently. Your powers can cut down small armies, and shield you from the effects of nuclear weapons. You are no longer merely limited to visiting other worlds and epochs from afar, but may now visit them personally. Powers are of comparable scale to Marvel’s Magneto and Doctor Strange.
Level 9 || That your powers rank less then omnipotent and have finite energy requirements are essentially your only restrictions at this point.
Level 10|| Anything becomes possible within the restraints of the rules of the forum and common sense.
The primary difference between this scaling and the AL system is that the AL relies on a numerical value each time you move up or down in scale, and so the scale only applies in one way; magnitude of power. The idea with this system is to account for two things: Power, and realism. This allows players to more accurately determine what level they want to play at by having two separate scales that interact with one another.
In regards to the power scale, each level can effectively be further codified into "high" or "low" - "high mild" or "low mild", "low advanced" or "high advanced" to give more flexibility to the tiers when further classification is needed.
Realistic is exactly what the name implies - as parallel to the real world as possible, in terms of physics, physiology, and the like. Minimal bends in the rules of physics, accurately portrayed humans, so on and so forth.
Semi-realistic straddles the line between purely realistic, and wholly unrealistic levels of combat. Combat will still roughly follow the real world, but the common addition of powers can more easily "bend" the rules. For example: the Shoryuken. A person can jump, spin, and punch all at the same time - not that it would necessarily be viable. But with a "nudge" of powers into the somewhat unrealistic, it can become a viable technique. A character could use powers to become stronger than normal, faster than normal, or the like, but without breaking the rules wholesale. Purely hand to hand or weapons combat would still by and large be somewhat along the lines of "movie realism", but with supernatural powers (if allowed), this can mean looser rules than in Realistic.
At the level of unrealistic combat, the rules of physics are loose, at best. A character could run up the side of a building indefinitely, dodge bullets, perform astounding acrobatics in mid-combat, or otherwise do things simply beyond the ken of realistic or even semi-realistic combat. Unrealistic is more common at higher power levels, because of the fantastic levels of physical abilities that many characters possess. Punching through a solid granite block, slicing through an enormous redwood tree with a single sword swipe, punching the ground hard enough to create an enormous crater - all examples of unrealistic combat.
Like Realistic, this is straight forward: a character has no powers, no supernatural abilities. They are more or less a human, albeit perhaps of Olympic level ability in terms of physicality. It can also be assumed that magical weapons or armor would also be banned, as they can give spell-like abilities.
Mild Powers is the next step up, and is harder to classify because you can take a higher or lower approach in terms of acceptable abilities. Characters can run the gamut from humans with powers (Naruto, Avatar, Street Fighter, D&D) to lesser demonic, angelic, or otherwise supernatural beings. At this level, a gun is fairly powerful, and might be barred from use. Essentially, a character will be balanced to have a few strong areas, and a few weak areas, as their powers and equipment are not sufficient enough to cover every possible situation or potentiality.
An example of a lower "mild powers" character could be Kyo Kusanagi, from King of Fighters. He is a hand to hand fighter without weapons or armor, but is at the peak of human physicality (and sometimes exceeds it), while he also has a fairly expansive "fire elemental" powerset which is close to mid range, and would (in roleplay) probably have a charge system reliant on chi or magical energy. Ryu from Street Fighter might also be an example. An example of a higher level "mild powers" would be if you took Kyo Kusanagi, and either expanded his powerset, gave him some mild magical items such as armor or weapons to expand his versatility, gave him a second powerset, or simply made him physically empowered beyond human limits as a permanent passive ability.
High powers can be defined by characters who are usually physically beyond the ken of human ability by quite a considerable margin (dodging bullets, hurling cars, etc) while also having considerable supernatural abilities. An example of this might be a super hero: A character with impossibly advanced physical abilities, super powers, and possibly some serious equipment. A lower end example might be Wolverwine: Adamantium skeleton, the ability to regenerate from practically anything, while being supernaturally powerful and potent in physical combat. He is on the lower end because, while he's exceptionally hard to keep down, he's also restricted to melee. At the higher end of the spectrum, you have characters who can destroy an building with a couple of preps, or even an entire city block.
Because it's been a while since I've played at this level, the description may be somewhat lacking: Essentially, a character at this level is potent enough to pretty much drop an entire city without too much effort. Think lower scale DBZ: Nappa, for example. Certain superheroes - like Superman - might also fit here.
At this level, a character can demolish a planet. Giant monstrosities, cosmic beings, so on and so forth are applicable at this level. Powers can be quite extensive, and a character may have several powersets. Freeza, Cell, and the like might fit in at this level.
At this level, a character is able to effect things on a universal or galactic level. Hurling galaxies at each other, creating black holes, creating or destroying planes of existence, planar psionics, so on and so forth. At this level, characters will very likely bend or break the rules of physics to their whim the manipulation of time and space is not wholly uncommon. Characters are likely to have god-like powers, and psuedo-science can be common, such as the application of string theory.