This is the beginning of the past of Collision Chaos for Sonic CD 510, below is an image from the final game.

Noticably the floors that Sonic stand upon have altered over time, no particular reason other than artistic choice.

Much like the rest of 510, Sonic does not curl up when entering a tunnel, he can simply walk around them and clip the walls.

In 510 these spikes have been placed, but do not appear in the final game.

This is the comparison shot for the image above. Also notice how in the final some of the sky is seen in the water below, but in 510 the water is completely orange.

In the 510 all of these springs are very uniform, with every second one being kept on higher ground. In the final they are fairly random, and also include diagonal red springs.

The beginning of the level is a little different also with the meeting of Amy Rose. The spikes which Metal Sonic barge through up upstanding in the 510, like any normal spikes. In the final a special floating set of opposing vertical spikes are in their place.

A small change of scenery at the ending of Act 1. Here we can see some grass in the backdrop, but is being hid by a piece of platform.

In the final level, the grass has been brought to the front. Here you can also see the difference in the water reflection.

Like most levels, the flowers are very different from 510 to final. The final is on the left, 510's flower is on the right.

The beginning of Act 2 for the 510 has a number of springs and tunnels leading to springs. While this is still like this in the final, they're all placed differently.

For comparison, this is the area in the final version. The beginning starts off very flat, but still has springs later on.

This past sign has been horribly misplaced in the Good Future of Collision Chaos 510.

Much like before, these springs are very uniform in the 510, while in the final they're random with diagonal springs added.

Despite being the good future, enemies still exist here. In the final all enemies have been replaced with flowers.

In Act 3 this orange item [seen above Sonic] will flip as Sonic passes it, but reacts differently in the different versions. In the final it will just play it's animation and not act onto Sonic, but in the 510 Sonic will stop in his trakcs and fall downwards, leading him into the spike pit below with little change of not getting hit.

Down here the 510 only has an empty area, but in the final some bumpers are merged into the floors.

Once Eggman is hit he'll take himself to the top, which has you hit him several times before he leaves. In the final he'll leave immedietly. He also does not throw bombs down onto Sonic in the 510.