Sonic the Hedgehog 4 Episode I (PartnerNET build)

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S4 Development Title 360.JPG
Sonic the Hedgehog 4:
Episode I (PartnerNET build)
Prerelease of: Sonic the Hedgehog 4: Episode I
System: Xbox 360
Source: Xbox Live PartnerNET

Sonic the Hedgehog 4 Episode I (PartnerNET build) is an early version of Sonic the Hedgehog 4 Episode I which was released on Microsoft's Xbox Live PartnerNET service. It contains many differences from the final game and includes different level designs and music changes. The iPhone port of Sonic the Hedgehog 4 shares strong similarities to this build.


In February of 2010, a build of Sonic 4: Episode 1 was submitted to Xbox Live Arcade's PartnerNET service, where developers are given access to upcoming downloadable titles for testing purposes. Soon after, screenshots, music and progressively more gameplay footage were leaked to the Internet. Eventually, a playthrough of the entire game had been leaked. In response to the leak, PartnerNET shut down for a night. The build was controversial, due to it containing "floaty" physics speculated to be due to its using the Sonic Rush engine, poor animations, and criticized level design such as gimmick-based Acts that were disliked by most fans.

On May 20, 2010, SEGA announced that, due to fan input, the game would be delayed until later in 2010, in order to extend the development of the game. They have stated in game magazines and on GameSpot's On The Spot that this was specifically done to allow various fan requests (since the game was leaked) to be implemented, including more momentum-based level designs and improved physics closer to the Mega Drive titles.

General Differences

  • No way to progress to the next act without using the Level Select screen.
  • Level select screen uses pictures of levels instead of a landscape.
  • Levels use the loading screen briefly, instead of animating the title card screen.
  • Incomplete Title Screen animation - Sonic appears in the emblem without rising out of it first.
  • Several other graphical effects are missing. Sonic's "wheel-of-feet" animation only appears when Sonic is at top speed, and Sonic lacks his glossier shading from the final build. No motion blur effects are present in this build.
  • After passing an End-of-Act signpost, Sonic hits an invisible wall at the edge of the screen which is not present in the final build.
  • By default the special stage and mine cart level rotation is controlled by L and R triggers and not the directional pad.
  • The cutscene that transitions Mad Gear Zone to E.G.G. Station Zone is absent.

Music Differences

Most of the music is identical to the final, but there were a few changes:

  • Casino Street 2 has a completely different song. It also lacks a speed shoes remix.
  • Since there was no World Map mode at the time, the level select used the menu music.
  • There was no transition between Mad Gear and E.G.G. Station, so this song is absent
  • Super Sonic uses the invincible BGM as he hadn't had his own theme yet.
  • Lost Labyrinth Act 2 lacks a speed shoes remix as there are no speed shoes in the level.
  • There is no sound effect played when locking onto a homing attack target.

Level Differences

Splash Hill Zone

  • The sunflowers in the background aren't fully animated; they are usually standing still.

Casino Street Zone

  • Act 2 contained the 100,000 Point Challenge, a short score attack level in a pinball-style area. Removed in the console version.
  • Act 2 had a different music track which was appropriate for the score attack level. Replaced in the console version.

Lost Labyrinth Zone

  • Act 2 contained the controversial Mine Cart level where Sonic remained in the cart throughout the level, which controlled poorly. The Mine Cart section is reduced greatly and plays automatically in the console version.
  • The moving wall in Act 3 was much faster and harder to complete the area compared to the final version.

Mad Gear Zone

  • Act 2's vertical gear ride was much harder, containing red parts where the gear slowed down and eventually stopped, along with a few Bubbles badniks during the segment. Removed in all final builds.

E.G.G Station Zone

  • The final boss lacks a few moves found in the final version.
  • The alert sound used at the last phase of the final boss is missing.



Sonic the Hedgehog 4 Episode I
Sonic4EpI PC title.png

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