"Shitty Wizard!"Valve's upcoming stand-alone sequel to the popular Warcraft III mod Defense Of The Ancients. Valve had hired Icefrog (One of the game's original developers) and have been working on a commercial sequel/remake of a sort called DotA 2. It was recreated on the Source engine with all-new graphics and UI. It is due in 2013, and a closed beta is now available. Recent updates about DOTA 2 can be seen here.
Dota 2 provides examples of:
Allegedly Free Game: Despite the fact that the game is completely play-for-free from the get-go, and you get every character from the start, the overwhelmimg majority of the online store is paying from your (Steam) wallet. For example, you have to pay to watch official tournaments in-game and not through a stream.
Exception goes to the yearly International tournament held by Valve. You can watch the in-game matches for free, and Valve makes money by selling "See it live" tickets and (for the 2013 tourney) the Compendium which is $10 for at least $35 worth of content and a promise for more as more Compendiums are bought.
Ascended Glitch/Good Bad Bugs: Creep stacking, a glitch in the original DotA, was fully replicated in Dota 2 due to the positive effect it had on gameplay.
The Artifact: The original Dota mod has three factions, including a neutral side, and normally defaults to allowing the Dire and Radiant to only pick from their hero pools and the neutrals. But completely open picking became ubiquitous in Dota, so the formerly neutral pool has been integrated into the Dire and Radiant sides. Thus there are True Neutral characters like Sand King on the Dire, and mercenaries like Bounty Hunter on the Radiant.
Backstories of various characters have been changed, in order to avoid references to Frozen Throne, since Dota is set in a separate universe, and Blizzard owns the copyrights to all elements of the Warcraft games, many of which were incorporated into the original Dota. However, even characters whose backstories have been radically changed are still in whichever side they were in the original Dota. So, while Centaur Warchief is a heroic saviour fighting for the Sentinel in Dota 1, his equivalent, Centaur Warrunner, is simply a Blood Knight on the side of the Radiant in Dota 2.
Boring, but Practical: Wards. Observer Wards only provide vision, but they are very cheap, and in this game vision is very important as knowing where an enemy player is heading means the difference between surviving a gank and feeding. Sentry Wards allow you to see where an invisible hero is, making fights against them much more manageable.
Call a Smeerp a "Rabbit": Quite a few characters, mostly with Sniper and the archers; Sniper refers to arrows as "feather bullets" and Windrunner refers to Sniper's bullets in turn as "tiny featherless arrows"
Cast of Snowflakes: Every character has unique appearances, abilities, backstories, and extensive responses to certain events.
Complete Immortality: A number of the characters (Keeper, Enigma, Chaos Knight, and Wisp) are Fundamentals: beings from the beginning of reality that are ageless and impossible to truly kill. The Radiant and the Dire are also Fundamentals, ones that were cast out by the others for constantly feuding.
Dem Bones: The Dire has quite a few undead heroes.
Disaster Dominoes: There's a lot of things that can go wrong: from your carry lacking a couple gold coins to buy an important item to the use of powerful ultimate abilities, that will make a team's situation progressively worse and worse even if it happened only once.
Evil Laugh: Very prominent. Almost every hero has a response of this sort to killing an enemy hero. Oddly, in this game it doesn't produce any Narm feelings, because whoever just scored a kill will usually feel like a badass, so if you get the laugh response it just makes the experience better.
Excuse Plot: Literally invoked in some of the supplemental material. The Heroes are mostly seeking their own personal power rather than being strongly for the Radiant or Dire.
Foe Romance Subtext: Between Kunkka the Admiral and Tidehunter of all people.
Kunkka: Ah, Tidehunter, you cared enough to hate me. You can't buy that sort of love!
GIFT: It's a MOBA game, so you can expect some of the playerbase to jump on you for even the slightest screw-up.
Better watch your back, because Bristleback is back! (kill me).
Homing Boulders: If a hero buys an item that gives them True Strike, which ensures that every attack will hit, it's possible for an autoattack to change direction in midair and fly across the map if the hero it was targeted on teleports away. This is especially ridiculous with characters like Sniper, whose bullets can spin right around in midair to chase their target!
Legacy Character: Due to copyright reasons (like belonging to Blizzard-exclusive races like Tauren or Pandaren) some characters had to be replaced. They are still easy to recognize. (It's pretty much no secret that Storm Spirit is a Panda.)
More than Mind Control: Non-heroes exposed to Direstone or Radiant ore quickly become warped by it and turned into creeps. This is ultimately reversible, though not without extreme effort.
Our Dwarves Are Different: While not outright stated, the Keen (Sniper, Tinker, Clockwerk, Gryocopter, and the smaller half of Alchemist) share similarities with Dwarves. Most are incredibly smart and sport facial hair, and are all very small in stature.
Random Drops: Incorporated using a system similar to Team Fortress 2, in that only cosmetic items drop.
Schizo Tech: Several of the Keen (ie, the Gnome analogues) have incredibly advanced technology, Tinker even having lasers, rockets, and automonous robots. They exist alongside and are routinely beaten by people using arrows and swords.
Gryocopter's backstory mentions finding an "incomplete schematic for a Gyrocopter, the world’s first manned, non-magical flying device". So, while technology, with the help of magic, is incredibly advanced, pure technology is mostly inept.
Standard Status Effects: Poison damage, paralysis, stuns, and silences are invaluable in teamfights. Several heroes (Venomancer, Viper, Silencer, Bane, and Spirit Breaker, to name a few) are themed entirely around a specific status effect.
Talking Is a Free Action: Characters regularly banter with each other. Not to mention, taken to ludicrous extremes with Storm Spirit, who takes this up to Lull Destruction.
Heroes will comment on loads of events, including buying a specific item, calling misses, killing certain other heroes, meeting certain allied heroes, getting a cosmetic item at the end of a game, and getting banned during the ban/pick process in Captain's Mode.
Touched by Vorlons: Several characters have abilities conferred by beings greater than themselves.
True Neutral:invoked Quite a few characters are empowered by various other factions to learn about the outside world, or otherwise care only for themselves.
Updated Rerelease: It has very minor differences from the original's gameplay, but has a new engine, brand new graphics and modern interface.
Several characters work differently because of the new engine, as the old Warcraft 3 engine put restrictions on certain spells. Rubick can now steal transformation skills (most notably Elder Dragon Form and Shapeshift), and Luna's Moonglaives work differently.
Visage is probably the greatest example of this. Three of his four skills were changed from the original.
Look here if you want a complete information of all lores in DOTA 2.
World of Ham: Every hero, even the most subdued, will mock enemies they kill and laugh when they score multi-kills. Also, nearly every hero will utter a hammy line when using a skill.
"JUGGERNAAAAAAAUT!"
"Come to PUDGE! Hahaha! Fresh Meat!"
"Where's the party? Zaaap! I'm over here! Puddin' pop! Here I am!"