I looked through the magazine scans on popuw.com.
While doing so, I found some screenshots which show things that are different from the final/released versions of PoP.
Maybe they are from earlier, work-in-progress versions, like those old SNES PoP screenshots.
DOS PoP
Differences from the released game:
- all: The prince has blue hair (or a turban?), and he is not barefoot.
- all: The wall patterns are different from the final game. Especially the dark bricks are at noticeably different places.
- top: The guard is all-yellow.
- bottom: The skeleton's skull looks different from the final game.
Comparison:
Sega Master System PoP
Differences from the released game:
- all: There are lines between the floor tiles.
- all: The torches are arranged quite differently. They seem to match the torches in DOS PoP?
- all: Hit points are not displayed.
- middle left: There is a gate in the top left room of level 1.
- middle right: The first guard of level 1 is a fat guy? And, I'm not sure if he's dying or just attacking (without a sword?).
- bottom left: A skeleton and a chomper are in a room which looks like the room of the second guard on level 1.
- bottom right: The jumping prince is closer to the ground than in the final game. The broken floor is barely visible.
Comparison: