Yesterday during Segas iPhone Games Day, easily the most impressive and fun game that I had a chance to play was Sonic 4. It finally feels like the Sonic game that weve all been wanting for the past 15 years, with no gimmicks, unnecessary characters or outlandish stories. Just pure 2D side-scrolling Sonic goodness, with heaps of Blast Processing. We previewed Sonic 4 during E3 in June, where we had a chance to play an early version of the game. Yesterday at Sega I was shown a nearly complete build of the game that included the previously unannounced Labyrinth Zone, two exclusive iPhone levels, and the special Chaos Emerald bonus stages.

The best thing about Sonic 4 is that its incredibly simple to play, to the point of almost rendering the virtual controls a non-issue. I say almost because it still can be tricky playing a platformer without tactile feedback, but with only an analog stick and one button to worry about it certainly simplifies matters. Sonic 4 plays similarly to the original trilogy where you can run down hills and roll through loops or perform a spin dash by crouching and mashing the button to build up speed, but one significant new maneuver has been added to Sonics repertoire. After performing a jump, you can hit jump in mid-air and execute a homing attack that will send Sonic spinning into nearby enemies or interactive objects which get target locked automatically. This adds an interesting dynamic to the game and makes it far more playable on the touch screen, as you dont have to be quite as precise when trying to defeat enemies.

Previously, Sega has shown off the first area of Sonic 4 called Splash Hill Zone. This zone is reminiscent of the beginning stage in earlier Sonic the Hedgehog games, with bright blue skies, green grass, and plenty of loops and hills. Yesterday they revealed Labyrinth Zone, which is also akin to levels from the old Sonic games. Its an underground cavern area with moving platforms, boulders falling from the roof, and underwater portions. This is also where one of the iPhone exclusive levels is based, called Lost Labyrinth Zone. This level has Sonic riding in a mine cart that is controlled by tilting the device while negotiating maze-like caverns. Sonic 4 deviates from the linear level progression of the originals, and once youve completed the initial Splash Hill Zone all three areas in each of the four zones are made available to play in any order. The catch is that you will not be able to play the fourth boss area for each zone until youve completed the previous three.

Another returning feature from the classic Sonic games is the addition of bonus levels. If you complete an area with at least 50 rings in your possession, youll have a chance to jump into a gigantic spinning ring at the end which will take you to a special stage and give you an opportunity to earn a Chaos Emerald. These stages are re-imagined versions of the ones from Sonic 1, and if you remember those stages youll understand just how well suited they are for tilt control. Whereas you controlled Sonic himself as the stage spun around you in the originals, in this iPhone version youll actually be controlling the stage by tilting and twisting the device while trying to get a stationary Sonic to the Chaos Emerald in the middle. Collecting a total of 7 Chaos Emeralds and completing the game will yield an alternate cliffhanger ending that will hint at things to come in Sonic 4: Episode 2.

Yes, Sonic 4 will be an episodic release. Sega couldnt comment on how many episodes will make up the entire experience, but have assured me that there is a definitive end to Sonic 4 and they wont just be releasing a new episode whenever they feel like adding a new set of levels. Sonic 4 is also looking quite stunning visually, and will be nearly identical to the console versions save for the 2 exclusive iPhone levels and tilt controls. Remarkably, the game runs at an incredibly smooth rate, and I didnt experience even one hiccup during my time with the game. Also of interesting note is that Sonic 4, the long awaited spiritual sequel to the classic original trilogy that fans have been clamoring for for years, will not be appearing on either the Nintendo DS or Sony PSP. While this may have Marcus in a huff, it shows just how committed Sega is to this platform and its fans.

This hands-on video from our E3 preview in June demonstrates Sonic 4 in action:

I can hardly describe just how much I enjoyed Sonic 4, and I cannot wait for the final version to be released. Sega wont pin down anything more exact than "sometime this Fall" but the game was looking mostly complete and hopefully it wont be too much longer before we can all finally play Sonic 4: Episode 1.