This prototype was released in August 2021. It's much more complete than the previous prototype, featuring five playable stages, but there are still a lot of differences when compared to the final version.

The prototype also has several issues with collision detection -there are many platforms that your character cannot jump on, instead, they just fall through them. Some of the hitboxes are misplaced, letting your character stand on air. But most of the time, this issue makes some stages unbeatable. If you intend to play this, look for the patched rom made by Lord Gambit, as this fixes the collision issues.

Gameplay differences

Sprite differences

Prototype	Final
John's idle stance only has two frames in the prototype. In the final, this was increased to three frames.

Prototype	Final
Eric's default spear has a much shorter range in the proto than it does in the final.

Prototype	Final
Eric's walking animation has him carry the spear differently between versions.

Prototype	Final
The mermen have completely different sprites in the prototype, and resemble their NES sprites more. For the final, they were redesigned.

Prototype	Final
The hellhound boss was another sprite that was given a redesign for the final version. The paws for the proto hellhound have some small squares on them which change color as he moves. Not sure what those are all about.

Prototype	Final
These things that move around some of the platforms in stage 2-2 were given new sprites in the final version.

Prototype	Final
The medusa heads have red eyes, mouths and necks in the prototype. The final version got rid of the red, and also brightened up their colors.