The game is definitely a big step in the right direction for survival-multiplayer PvPvE games. I'm not trying to sell the game to anyone with my personal opinion. I will however point out features I appreciate.

Features that stand out to me:

Tutorial / Game Manual
- Tutorial / Quest system to guide you from Beginning to End Game
- PDF extensive game manual 120 pages (access from your steam library / below achievements)

Sandbox - Open World - PvPvE
64km map (approx. 25 square miles)
Official Servers PvP & PvE (Cross server transfer & travel system available)
Custom & Private Servers

Player activities
- PvP & PvE -- FULL LOOT
- Quests - Daily, Weekly, Tutorial/Guide, Guild.
- Siege systems for Players and NPCs
- NPC Camps, Cities, Forts
- "Dungeons"
- Treasure hunting (unique items, recipes, rare items)
- Survival against elements Cold, Heat, Poison, NPCs, Hunger and player toxicity systems.
- Animal taming / breeding
- Camp to Town to City to Empire management available
- Extensive depth and character (and NPC) development
- Extensive crafting depth (at first glance the crafting may look basic, it is not)
- City / Resource point claiming systems
- Leaderboard system (tied to activity points)

Crafting System
- Basic crafting to advanced specialization crafting
- Advanced quality crafting system (skills & talents - colored crafting levels)
- Durability & Efficiency systems
- Tools/Weapons/Armor usages tied to skill specialization system (using an iron sword with 0 skill in one hand can hinder the weapon and penalize the user)

Building systems
- Building quality levels tied to skills & talents
- No terraforming
- Place and snap to building (un-snap is toggle)
- Buildings have durability and decay if unprotected
- Numerous crafting tier levels ie Wood, clay, etc.

Guild Systems
- Guild leveling
- Alliance systems
- Prestige systems
- Guild specific skill trees to benefit players / playstyles
- Guild specific tech trees for guild specific buildings

Player customization and depth (deeper than most RPGS)
- Nobility perk system (a long term character growth tree)
- Skill proficiency systems (respec & adjustable)
- Skill specializations
- Perk system (mid-late game)
- Numerous Skills & Talent trees
- Tactic skill system (skills from mid-late game activity)
- In-game achievement system tied to "minor" permanent character stat increases
- Perk system tied to map exploration (you must find shrines hidden throughout the world to get perk points)

Human NPCS and Creature NPCs
- Tame / Breed creatures for materials
- Tame / Breed horses for riding, hauling, warfare
- Recruit / capture / convert Human NPCs to become workers / warriors
- Human NPC stats are similar to player stats & growth
- Human NPCs can have strengths or weaknesses ( you could get some really rare & unique NPCs)
- NPC Equipment system for Horses, Warriors, Workers, and AI-NPCs. (you can equip your warriors/workers, just as you can knock out and steal items from NPCs)
- Permadeath system (note: this system is forgiving and happens only after certain conditions are met. You can lose a horse or Warrior and revive them initially, repeat loses can lead to a permadeath)

Auction house system
- Horse auction
- Warrior / Worker auction
- Item auction and more

PvP & PvE Official servers
- There is not a single shard or single map
- ALL Servers can cross travel between one another
- Single character only for all official servers

NPC Factions
- Low faction will result in KOS
- Low faction can result in NPCs raiding your base or attacking you in open world
- Faction applies to animals/creatures as well (over hunting boars can have negative outcomes for your person or guild)

*** ADDITION ***
05/24/2023
Still going strong!

*** ADDITION ***
7.24.2021
and.... Still enjoying Path of Exile.

*** ADDITION ***
8/15/2019
6 years later, and I am still hooked.

*** ADDITION ***
8/19/2014
Here I am almost a year later and still the game has kept me hooked, and deeply involved. There is a new expansion coming out tomorrow that will, in my opinion, change many faces of the game in good ways for both new, casual, and hardcore players. The Forsaken Masters expansion will add more life, and flavor to the game. As well add in "player housing" essentially, which is a huge deal for an ARPG game. Something I personally have never considered in my "want list" for an ARPG yet at the same time, I can see how great a tool it will be while playing.

*** ORIGINAL ***
10/23/2013
Diablo 2.5 and then some. This game is amazing on so many levels. It is free, try it and judge it yourself. I recommend setting aside several hours of playtime. I do not recommend playing this game with a comparison attitude, IE. "Is it like Diablo 2 / 3?" It is it's own game with strengths & weaknesses of it's own.

This games core values lie within it's character customization / skill tree & skill gems, and within the loot / end-game maps. The game itself really does not begin to shine until you get into Merciless difficulty, in which also opens the end-game map system in Act 3. If you are unable to get to this area of the game, you will be unable to fully appreciate some of the above noted core values of the game.

I have seen many players, friends included that have been unable to get to Cruel difficulty, or out of Cruel. I recommend going on the PoE official forums, to the class forums, and finding some builds other players have created, to better verse yourself with proper character building. Your character build, gear, and player skill are all factors in this game.

I have enjoyed this game greatly from standard - hardcore. I've lost several 50+ hardcore characters, and I keep going back, it's addicting, and enjoyable. This game has so much to offer that there is no way for me to truthfully summarize it all, you just have to get in, and give it a shot!
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Thanks GGG for such a great game.