Frozenbyte has unleashed the much-awaited sequel of 2009's indie sidescrolling platformer today, with digital copies for PC and Mac readily available through Steam. Pricing is set at $14.99, while a $24.99 "Collector's Edition" includes a digital artbook and soundtrack. Although professional reviews are still pouring in, the few that are around have praised the game's lighthearted action, fairytale visuals and stimulating physics-based puzzles.

Trine 2 has improved upon one of its predecessor's most attractive features: co-op gameplay. While the original was strictly an offline two-player affair, today's release can support up to three players online or locally. You shouldn't have any problems convincing a buddy to join you, especially considering the meager $15 admission fee. In fact, we're surprised Steam isn't taking the opportunity to sell a slightly discounted three-game bundle.

Naturally, there are plenty of other improvements over Frozenbyte's initial project. Based on the launch trailer below, there seems to be much more creative and challenging puzzles, not to mention the characters' new abilities, which includes frozen arrows and monster levitation. To complement the trickier sequences, you can now save whenever you want. The original had predetermined checkpoints that set you back if you died.

Spec-wise, virtually anyone with a halfway competent PC should be able to play. Frozenbyte specifically calls for a 2GHz dual-core processor, 1GB of RAM, 1.5GB of storage, and a Radeon HD 2400 or GeForce 7600 or better (Shader Model 3.0 needs to be supported). Even Sandy Bridge's HD Graphics 3000 IGP is invited, though the developer warns that the game might be a bit much for most older integrated solutions to handle.

Going forward, Frozenbyte plans to release Trine 2 on the Xbox Live Arcade and PlayStation Network on December 21. Beyond that, the developer has promised to follow-up with a fair amount of downloadable content. From what we've heard, there's about four hours of extra gameplay in the pipeline for PC players, which equates to roughly 50% of the base install. There's no word on how much the DLC will cost, if anything.