Icecap has many notable changes that were cut from the final release. It has a more wooden appearance than the one in the final, and the small ice decorations around the level are smaller. The wooden appearance is caused by global texture ID conflicts, as opening the stage in a model viewer shows the appearance of the stage as it appears in the final game, without the random wood textures.
The bridge seen in early images of the game is present here:
Early Screenshot
AutoDemo
The start of the level is missing a Tikal hint ball and an Ice Ball:
Proto
Final
The small tunnel at the start only has one dash panel and it's placed at the end rather than two at the beginning of it and a line of rings.
The dash panel sends Sonic into a spring that doesn't exist in the final.
The area at the bottom of the hill is completely empty other than the icicles preventing Sonic from going further. The jump panel area and the dash panels are missing.
A dash panel near the entrance to the cave that sends Sonic into the spring to bounce him up there was replaced by a line of seven rings in the final.
There are three enemies present on the hill that are not in the final - an Ice Ball and two Boa-Boas.
The item boxes at the top of the hill are missing.
Immediately upon entering the snowy cave the player meets a line of four rings that aren't in the final.
To the left of the cave entrance is a circle of rings that isn't in the final.
There are a lot of wooden textures. In the final, these were replaced with standard walls.
There is a curved line of four rings across a small hole to the next platform here. In the final, there is a hint ball, a spring, and a platform covering up the hole.
There is a spring to send Sonic into the hanging icicles. This was replaced with a small platform in the final.
There are 10 hanging icicles here. In the final, two at the right end were removed and a platform was added below to compensate.
Taking the middle path at the icicles sends Sonic into a small platform. In the final, the platform was enlarged with platforms.
Jumping on top of the icicle area are five rings that are not in the final.
Taking the right path at the icicles sends the player to a platform with five rings, a "?"-ring box, and a spring over a small hole. In the final, there are four rings, fences, and the hole near the spring has been covered entirely. There are also boxes next to the spring not present in the final.
To the right of the spring are 3 tiny platforms. In the final, boxes were added and the small platforms were reduced from 3 to 1.
There is an area after the platforms with a 10-ring box and a 1-Up box. In the final, the 10-ring box is removed and the 1-Up box is moved to its former location.
The entrance (technically an object) to the 2nd Act 2 is not solid.
The rocket platform is missing. Instead, there is a bridge in its place. There is also an extra checkpoint at the end of the bridge that in the final was moved to the beginning of Act 2 instead.
Act 2
There is no rock behind you at the start.
There is a single spring floating out of bounds, where Big's part of the level would be located.
There are boxes when you leave the cave. In the final, this was replaced with a checkpoint, fences and rings.
There are two Ice Balls at the bottom of the cavern. In the final, they have been replaced by a Boa-Boa.
The spring at the bottom of the cavern had 5 rings added to its path in the final.
Between the first and second springs, there is a slightly misaligned line of 5 rings. In the final, this was replaced with a line of 4 rings and two spikes.
The area below the first hanging icicles section is empty aside from a spring sending the player back to the beginning of the area. In the final, many spikes were added as well as a spring allowing the player to skip the icicles.
The first icicle section has 5 icicles. In the final, two more were added and the icicles are closer together. The spikes near these icicles in the final are also missing.
The spikes near the line of rings after the icicles are missing.
There is a small hole that the player must jump over with a curved line of 5 rings. In the final, a spring was added, the line of rings was reduced to 4 and a small platform was added over the hole to prevent the player from falling.
There is a switch that does nothing next to the small icy pool area. (Presumably an ice block switch.) There is also a small line of 3 rings floating nearby. In the final, this was changed into an arrow of rings:
Proto
Final
Under the floating rings is a small area with a tiny platform for the player to use to climb back into the icy pool area. In the final, this was replaced with two springs, with one allowing the player to progress.
There is a small hole in the wall after the floating rings section that does not appear in the final.
A 10-ring box next to the location of the small hole in the final is missing.
A dash panel leading into the second icicle section is missing.
The area below the second icicle section is empty aside from a spring and some fences. In the final, an Ice Ball was added as well as a circle of rings.
There are six icicles in the second icicle section. In the final, the same changes to the first section were applied - the icicle count was brought up to seven, and spikes were added nearby.
Two circles of rings are missing from the area after the second icicle section in the final.
The spring in the area after the second icicle section is also in a slightly different spot. The rings were not corrected in the final.
The area with the floating ice block switch is empty aside from the switch. In the final, the switch was moved slightly to the left and a Tikal hint ball and fences were added.
The checkpoint after the ice blocks section is missing.
The dash panels at the loop area are missing.
There is no Tikal hint ball at the first jump panel.
The boxes around the first jump panel are slightly different.
There are three jump panels. In the final, a fourth one was added.
Three ring boxes in a small area to the left of where the jump panels end are missing.
The end of the tunnel to Act 3 is not solid.
The spring panel.
The two pools left over from Big's stage. The pool on the left was removed entirely in the final.
Act 3
The gate at the start is facing the wrong way.
The beginning of Act 3 continues to play music. In the final, the level is silent until Sonic triggers the snowboarding segment.
Sonic does not make a screaming sound in the small cutscene where he notices the avalanche.
Instead of focusing on the snowboard in the cutscene as Sonic walks off the platform he's standing on in the cutscene, the camera follows Sonic closely.
The snowboard instantly appears under Sonic.
Large rocks at the sides of the mountain are missing:
Proto
Final
There are fewer icicles along the course than in the final.
Sonic's snowboard incorrectly plays the icicle breaking sound sometimes.
There are three dash panels to the right after the avalanche section. In the final, there's two.
There are many dead trees on the mountain that were removed in the final:
Proto
Final
The first falling ice arch was moved further up the mountain. One was also added on the side path to the right in the final.
Sonic makes a different sound performing a trick.
The first set of trick ramps are spread apart with a gap between them. In the final, they form a "double-ramp".
There are no rings in the last caved area.
There are no hot air balloons.
There is a double trick ramp after the last cave. In the final, this was reduced to one ramp.
After the ramp on the small land between the two ramps is a dash panel and a line of rings that was removed from the final.
The end of the stage looks completely different - the capsule is in a slightly different spot to the final, there are no houses at the end of the stage and more trees.
Proto
Final
Act 4
Sonic has his own object layout for Big's Act that is an earlier version of the stage. There are many leftovers from Act 2 present that do not appear when playing as Big, such as ring trails near the top of the stage. However, many objects are incorrect in Sonic's version of the stage.
Big's level with the incorrect objects as Sonic.
This area is empty as Big, but incorrect as Sonic.
When playing as Big:
There are Ice Balls here that aren't in the final.
Big can't break the ice.
There is an underwater area under the smaller icy area at the start of the stage. In the final only the large icy area has an area under it.
The water is not animated and a lot of the underwater sections are not considered "underwater" by the game.
Much like Sonic, Big's level does not have spikes in it.
The area where there is an arrow of rings in Sonic's version of the level in the final does not have any objects. In the final, there is a Speed Shoes box and a spring.
The small icy pool halfway through Sonic's route is still icy in Big's section. In the final, it's a pool of water.
The small platform to the side of the area where the jump panels end in Sonic's version has a rock on it. In the final, this has been replaced with two "?"-ring boxes.
The areas in Sonic's route after the area with the arrow of rings in the final is completely empty. In the final, this area is filled with springs, platforms, rings, and item boxes.
