Sonic the Hedgehog 1 Beta - Marble Zone

Beta version is missing two pillars, and has an extra Yadrin robot. Some people say Yadrins were replaced with Caterkillers in the final version. Those people are wrong. You can see there is no Caterkiller in the final version where the Yadrin once was. The beta version probably had both Yadrins and Caterkillers, since the graphics for both robots are loaded into the VRAM.

Same screenshot as above, but you can see the planets/UFOs in the background. They were probably objects that moved across the background, rather than being part of the background tiles themselves.

It looks as if the flame is missing in the background of the beta version.

You can just about see the plantes/UFOs again in the background.

This area of level isn't in any of the 3 acts.

"RING".

"RING" again.

...and again.

...and yet again.

The beta version has an extra obstacle - a sideways-facing spiked block that moves back and forth. It's replaced by a row of harmless green blocks that you can stand on. Less noticeably, the platform on a chain is wider in the beta version.

The spikes object is still in the game, and can be restored by hacking, as Iceknight has done here.

This is a scan of a collectable card, which has clearly been modelled on the beta version of Marble Zone.

This appears to be a mock-up screenshot, or concept art.

A better screenshot of the UFOs.

Missing green crushing blocks, missing torch flame, different lava, slightly different layout.

A good screenshot of the UFOs. The moving platform on the right is different.

Here are four screenshots from Wayne's World. They show how the UFOs rotate.