The 76 metascore is the result of what Magicka was when it came out: A hidden gem executed okey-ishly and with some bugs. But that's way too far from the game Magicka is today...
Which is one of the best Local-Multiplayer/Co-Op/Versus games in all of Steam. I was a late buyer so I got to skip all the supposed bug-fest, but let me tell you this: Right now, Magicka is a blast to play with friends. Be it local or online multiplayer, co-op campaign or versus or survival, with keyboards or with controllers or any mix of all of the above.
Aside from the super-robust level of multiplayer options, the game's campaigns (main and all of the DLCs) are amazing. The main campaign is filled with easter eggs, little details everywhere and stupendous and magnificent narrative comedy. I'll be frank and admit I haven't finished most DLCs yet (as I wait until all my buds can get together to finish them in one sitting), but I can tell you that The Stars Are Left, The Other Side of the Coin and Dungeons And Daemons are worth every penny.
The quality for your money also applies for multiplayer-oriented DLC, which is cheap and adds lots of cool themes, robes with different stats and abilities and weapons that range from The Doctor's Screwdriver to Ak-47s and of course a ♥♥♥♥♥♥♥♥ amount of staffs.
The gameplay is a bit hard to explain as there are truly no games like Magicka: Top down isometric spell casting & mixing shmup with always-on friendly fire is the shortest way to put it. The long one is: You see your wizard from a top-down-with-an-angle perspective, you can cast 8 elements: Fire, Life, Electricity, Water, Cold, Earth, Arcana/Death, and "shield" which gives any combination of elements a defensive use of sorts. All this elements are on their own very weak but once you combine them you can get deadly creative. From mini-volcanoes that light enemies on fire and explode when touched to steam-compressed mines that send foes (and friends) flying away Team Rocket-style to Death-electric beams that freeze to freaking Meteor Showers to casting Death Itself (whom kills someone on-screen at random).
Now remember that the game has always-on friendly fire. Yup, it's a madhouse.
If Mario Party destroys friendships, Magicka will obliterate blood-related family ties. But in the nicest, funniest and best ways.
As a lover of couch co-oping, well-executed games, friendship, and... well, games in general, I urge you, TRY MAGICKA. It's very unlikely you'lle ever regret it.
Unless you have no friends, of course. Being burned/electrocuted/bombed-away/exploded into tiny pieces accidentally on purpose is not as much fun when a complete stranger does it.