Some of the most noticeable changes that pertain to League of Legends:
- Champion selection is limited to the "free to play" champions (which are rotated on a weekly basis) or the ones you have purchased using in game points (Influence points) or real life money (converted into Riot points).
- Maximum level is 18. With the exception of (as of writing this) 2 champions, Udyr and Karma, this gives your Q, W, and E skills 5 levels, and your R ultimate 3 levels. For Udyr, as he has no true ult, but rather 4 basic skills, you could have a 5 5 5 3 setup, or a 5 5 4 4 setup, or any combination therein. For Karma, her ult is given at level 1 and never levels up, giving her Q, W and E skills 6 levels each.
- No denying. This includes towers
as well as creeps/minions. You can still deny by keeping enemy champions out of the kill radius / prevent them from last hitting, but there is no "auto-attack your own minions" to deny.
- No gold loss on death.
- Towers hit a lot harder and do more
damage to you the longer they've been
hitting you, making early tower dives
a lot riskier and making towers much
safer to defend against.
- You can kill the enemy base/nexus
without having to kill the 3 inner
lane turrets. You still must kill the
2 nexus towers first, however.
- The ranged/melee barracks have been
merged into a single building called
an inhibitor, and instead of
bolstering the melee/ranged minions
in that lane when destroyed, it
instead makes a single, powerful
melee unit spawn with every wave.
Inhibitors respawn over time.
- There are far fewer "active" items
(click to use) and the focus is more
on increasing your passive stats.
- Every champion has a passive ability
that is somewhat integral to their
playstyle or their character flavor.
These passives are always active and
require no skill points. For example,
the champion Zilean increases all
allies' experience gain by 8% always. A more active example would be the character LeBlanc, who spawns a mirror image whenever she drops below 40% HP (occuring at most once per minute).
- There is a 3v3 as well as a 5v5 map,
meaning there are two separate
meta-games to identify (though most
people play 5v5).
- Some of the larger neutral creeps
provide passive buffs that provide a
visual effect as well as a bonus to
attributes. For example, the Golem
buff provides mana/energy
regeneration and cool down reduction.
- There is a large neutral creep called
the dragon that provides teamwide
gold and experience. This is often
contested through the mid-late game
and is a prime target for jungler
champions to kill.
- The "boss" neutral creep (Baron
Nashtor) does not provide an item
(like Token of Life), but rather
teamwide gold/exp and a passive buff
that greatly increases
health/mana/energy regen as well as
additional attack damage and ability
- You get to choose 2 additional
"Summoner Abilities" that are
universal regardless of what champion
you pick. Some examples of these are
Ghost (temporary speed boost and
unitwalking), Flash (short range
teleport), Ignite (scaling damage
with a DoT and reduced healing/regen
component), and Clairvoyance (short
cooldown, small radius map reveal).
There are others too, of course.
- No river runes.
- You may passively increase your
champions' stats by purchasing
"Runes" outside of the actual in-game
interface. These runes are purchased
using points you earn by playing
games (winning or losing).
- Additionally, you may increase your champions stats / enhance your "Summoner Abilities" / provide passive effects through the mastery system. The mastery system is a simplified version of a talent tree (akin to Diablo 2, World of Warcraft, etc.) with points being earned as you level your summoner (your account), which is done by simply playing games.
- Ability to return to base (free, no need to buy it, no item slot taken, no cooldown)
- Improved juking - instead of sneaky paths between trees there is "brush" (bushes/grass) system - brush blocks line of sight of those outside it and provides bonuses to some champions/heroes
- Map is symmetrical with the exception of the placement of the Dragon and Baron "boss" creeps.
- Shields system - damage shields are dynamically displayed as a gray extension of the healthbars. Purple extensions indicate magic-only shields.
- It's possible to bind smartcasts (cast instantly on keypress on the area the cursor is hovering over, not on an additional mouse click)
- No secret shops or outposts. All items are purchased at the base shop.
- The Shop's combination items are displayed in a tree, making it easy to see which items combine into what.
I'll add more as I think of more. Hope this is a good start for you!