Sonic X-treme bosses
From Sonic Retro
Similar to most games in the Soinc the Hedgehog series, Sonic X-treme was meant to have a boss battle after the successful completion of an entire Zone. Though at some points in development it would have been possible to play the acts of a zone out of order, the end result was always to be the same: for the game engine to switch from the Ofer Alon-designed stage engine to the Christina Coffin-designed boss engine, removing the fish-eye lens in the process.
The boss encounters for the game were meant to be in a NiGHTS-esque arena, where the player would fight against an oversized enemy such as Metal Sonic or Fang the Sniper. The reasoning behind the large enemy was simple. Christina Coffin, knowing this would be players' first experience with Sonic in a 3D world, wanted a target that would be easy to hit, a larger enemy possessing a larger hit box.
The furthest along in terms of known bosses in the game, Metal Sonic's boss fight was fully programmed into the game, with a rudimentary form of aggressive AI that would charge Sonic the Hedgehog. While Chris Senn had drawn up a number of possible variants to Metal Sonic, none were actually utilized during the production of Sonic X-treme.
Fang the Sniper
While most of what is known about the proposed boss encounters is restricted to concept art and screenshots, two boss encounters were given the full writeup, as explained on Chris Senn's Sonic Xtreme Compendium.
Mecha Mite Boss
Deep within the abandoned oil mines rests the Wind Element Keeper. Hibernating just below the oil lake, the Mecha Mite Boss is rudely awakened by our trespassing hedgehog and begins to lift itself from the black muck. This huge creature upsets the balance of rock and oil pockets and starts a chain reaction- As shards of sharp clay and rock fall into the shaking lake below. Oil oozes steadily out of reopened wounds in the cavern's walls. The whole earth shakes as Sonic's new challenge becomes apparent. Sonic is protected (for the moment) within a 6-tiered, cylindrical glass tower. On each floor, facing either North, South, East or West is a metal pipe that Sonic must spindash into to reach the floor above. Time is limited as the oil steadily rises on the outside and within this structure. An enemy or two will harass Sonic before the entrance to each pipe. Meanwhile, shaking and clawing its way to the top of the tower is the Mecha Mite, dripping with oil. Once Sonic reaches the top, the pipe he used crashes down into the now-paused muck. The Mecha Mite Boss attacks first by rising up and opening its immense three jaws to blow "oil wads" at Sonic. The Boss can also suck in huge pockets of air- Sonic must stand behind something or be pulled into the nasty, teeth-ridden jaws of Mecha Mite. Occasionally (and constantly before its death) the Boss spits out an appropriate enemy to attack Sonic. The final stage for this Boss is when it rises above the tower and holds onto the top with its claw appendages. Sonic must destroy these to send the Boss falling to its death.
Darkpool Gorilla Boss
Eventually, Sonic will make his way to the Boss zone - A huge cavern a thousand feet below ground. The walls of this huge spherical domain have been carved out by years of underground streams trickling slowly down its sides settling in a dark pool at the bottom. Several paths lead towards the center, where a tall, rocky pedestal juts up from the murky base. Atop this rests a huge hydraulic platform upon which a dark hunched figure stands dormant. Once Sonic reaches the overhanging straight pathway to the center platform, still leaving about 30-40 yards between, several things happen. First, a mechanical humming and drumming fills the thick, musty air. It is like some machine waking up after thousands of years of hibernation. A few indicator lights below the platform flash and come to life. The dark figure's eyes light up red and it suddenly stands erect. Stones and clumps of dirt crack and slide off of this Boss's massive cast-iron body. Twisting his upper torso from left to right a few times (as if waking up and stretching), the Darkpool Gorilla Boss sees Sonic and does a double take. Slamming the surface of the platform sends a quake right through the rickety bridge Sonic is standing on. Immediately, it starts to give way behind Sonic and the only way is to run forward to the frenzied Boss or fall to death. The hydraulic platform tilts according to weight change and Sonic's first test is to try and defeat the Rock Elemental's Boss suit On this teetering square. After defeating him, the platform sinks down on its piston base and activates two exit balls for Sonic to choose between.