Unique and awesome game that any Warhammer fan must play!
I love this game :3 I have so much fun playing this with my Brother and solo.

Kill hundreds or thousands of Skaven on different and cool maps following a story line.
The Characters hurl insults at each other and have entertaining banter while you play.
There are random events and enemies making the missions more replayable.
There is a stats screen after missions but just ignore that. Different characters and classes have different roles, some tank, some clear hoards, some kill specials/bosses etc. This game isn't about high damage, its about strategy, skill and team work.

Difficulty:
Recruit - Easy hack and slash. If you get separated from your team you will die. But if you stay together its easy.
Veteran - Harder Hack and slash or may require some skill depending on your equipment. Stay together, revive and help team and its manageable
Champion - Learn to Block and Dodge or you die, this is not a hack and slash game, skill required, git gud or die. Careful of friendly fire!!! Take care of team or everyone dies.
Legend - More difficult than Champion and easier to kill team with friendly fire. Bots/npc team mates will become useless at this difficulty. You need skill and good equipment and team work to survive. Edit: Just played this after Champion started to feel a lot easier, and was easy-ish until someone needed reviving, then everyone else died trying to res. Definitely an unforgiving difficulty. Small mistakes potentially lead to everyone dying. Also has way more special enemies than Champion
Cataclysm - Death, only the highly skilled can maybe survive this.

Ways to die:
Assassinated - need team mate to save you
Eaten - need team mate to save you
Leeched - need team mate to save you
Caught in hurricane - need team mate to save you
Pushed/Fell off map - need team mate to save you
Strangled - need team mate to save you
Dissolved in Bile
Gassed
Burned
Fell from great height
Stabbed
Shot
Caught in Explosion
Walk in acid
Fell through map due to glitch - Unavoidable
Death by friendly fire at Champion and higher difficulties;
- Friendly fire from team mate Kerillian shooting you, either bad shot, forgot about friendly fire or you accidently walked into it
- Friendly fire from team mate Sienna accidently blowing up and dying if the player is inexperienced or an Unchained that has taken too much damage, if you see her overheat run.
- Team mates throwing Bombs
- Other ranged attacks from team mates hitting you will cause damage

and theres probably more I'm forgetting xD
Also there's even more ways to die in the Winds of Magic dlc

Characters:
5 characters with 3 careers each to choose from (4th careers are dlc)

Markus Kruber - Human
- Mercenary - Was awesome with Executioners Sword before they nerfed it. Healer like Career skill but hes not a healer, great at killing and staying alive. Hoard Clearer
- Huntsman - Ranged class
- Foot Knight - Why play this when Ironbreaker exists?
- Grail Knight - Awesome special and boss killer, no ranged attack

Bardin Goreksson - Dwarf
- Ranger Veteran - Trash Career at first, great if you know what your doing
- Ironbreaker - Best Tank in the game, maybe best career/character too
- Slayer - Badass Damage dealer, lots of fun but block while jumping into enemies, your not invincible :P
- Outcast Engineer - Awesome but don't forget to crank your gun! :D

Kerillian - Elf and best character in the game in terms of abilities
- Waystalker - Archer and Special Enemy Killer
- Handmaiden - The melee class with the best dodge in the game
- Shade - OP but dies easily especially to a random slaver you missed

Victor Saltzpyre - Human Witch Hunter
- Witch Hunter Captain - Ugly but awesome survivability at cataclysm
- Bounty Hunter - Looks cool and does high damage
- Zealot - Badass killing machine, low health = high damage

Sienna Fuegonasus - Badass Fiery Battle Mage
- Battle Wizard - Awesome. Different staffs do different fire attacks. Some staffs are hoard clearers, some staffs are special enemy killers and who doesnt love fire and explosions! :D Good for Cataclysm
- Pyromancer - Havent played it
- Unchained - The most badass looking class in the game and tanky too while doing great damage. Passive turns 50% of damage into overcharge meaning your more likely to die from blowing up than dying from losing all your health. But her active ability allows you to clear your overcharge and is like a panic button if surrounded by enemies or about to explode from over heating. The Unchained is also the melee version of Sienna and pro players can use her other passive to do a lot of melee damage by keeping her on high overcharge, unskilled players will likely blow up though. Difficult but awesome.


But in order to unlock each career you need to level the character up to a certain level.
Like Sienna, you start off as a Battle Mage, when the character reaches level 7 you unlock Pyromancer, when Sienna reaches level 12 then you unlock Unchained.
Also characters and careers are separate things.
The careers are like different characters, some equipment for a specific career but other equipment is for a certain character regardless of career. Also the character will level regardless of what career your playing. So if you want to level a career you don't like or is weak, you can play the same character but a different career.


If you want to play alone that's fine, sometimes the Bots/Npc team mates are better than other players anyway.
Especially the people who think its a good idea to run off ahead of the team or not revive team mates, because those players end up dying and needing to revive anyway. Rule 1 of Vermintide - Stay together or Die. The Bots seem to use what ever the Leaders load out for that character is, making my brothers Markus Kruber Bot a damage kill stealing tank.

Tomes and Grimoires
Collecting these will give you better loot when you finish the mission but makes the mission more difficult. I recommend you play with others to learn where these are hidden on each map or if running solo you need to do your research, google or youtube. Some of the places these are hidden is ridiculous but makes the game interesting to explore.

Assassins Creed reference
Theres an assassins creed reference on one of the maps which requires you to parkour a tower, also you can train in the built in parkour part of the base you always return to.

Probably committing a cardinal sin here, some of the community doesn't like talking about bugs and wants you to forget them but if your buying something you should know;
This game is a buggy mess, 80-95% bugs are harmless but all the bugs are very noticable.
- Was playing with my Brother and he suddenly fell through the floor and died outside of the map for no reason once.
- I was playing with my Brother and 2 randoms and this barrel we needed to place somewhere fell off the map into some water when the person carrying it died and we couldn't get it back and it couldn't spawn back. It was stuck in the water out of reach glitched. It should have respawned.. When one of the randoms died again I took their bombs off their corpse and managed to blow it up. But if I didn't have that idea or we didn't have any bombs left, we would have failed the dlc mission.
- Skaven sometimes walk through walls, or in the air or walk straight passed you in the air without realising at first etc.
Actually.. I could be here all day writing about the bugs but since most are harmless just ignore them and have fun killing Skaven ;)
Also this isn't a bug but as awesome as the maps are, there is small holes in the mesh, there are a few inconsistantly sized blurry textures and other mistakes the team has made making this game. But maybe they'll eventuallly fix it at some point?.. One of my top 20 fave coop games to play regardless ^^