Magicka was an immensely fun co-op game in which almost as much joy could be had from "accidentally" splattering your friends with a wayward spell as there was from actually playing it "properly."
It is, therefore, somewhat unsurprising that there's a full-on PvP version on the way. Some DLC for the original Magicka provided the opportunity for players to go head-to-head against each other, but it didn't prove all that successful; Paradox is presumably hoping that the allure of free-to-play will convince more people to try the new Magicka: Wizard Wars for themselves.
I say "free-to-play" but you can't actually play Wizard Wars for free just yet; it's one of a growing number of free-to-play games charging to let you in to its Steam Early Access version. Like Snow, which we reported on recently, there are three "tiers" of early access available, each of which offers you a selection of in-game rewards as well as entry to the game during its testing period.
The $12.99 Starter Wizard Pack provides you with a green robe, three weapons, a forum avatar and a forum icon. The $19.99 Founder Wizard Pack provides you with yellow and green robes, three weapons, two forum avatars, a forum icon, access to the "Dev's Dungeon" forum, a credit on the Wizard Wars website... and, rather generously, a copy of Crusader Kings II (worth $39.99 right now). Finally, the $49.99 IMPressive [sic] Founder Pack comes with four weapons, three robes, the ability to name an in-game imp, imps with special "founder's hats," three forum avatars, a forum icon, access to the "Dev's Dungeon" forum, credit on the website, $20 of in-game currency for when the game launches for real, three additional alpha invites to gift to friends and, again, a copy of Crusader Kings II.
The trend of charging for early access to free-to-play games appears to be growing somewhat. This would seem to go somewhat against the very idea of "free-to-play" but it is often positioned as helping to support the continued development of a new game in exchange for getting a first look at it. In Wizard Wars' case, the rewards are at least reasonably generous -- particularly in the upper two tiers, which give you a free copy of a $40 game (albeit one that is frequently in Steam sales) as well as your alpha access pass.
If you want to get in on the Early Access fun, head on over to the game's Steam page; if you'd rather wait to try it for free, meanwhile, the full game is set for release in 2014.