Have you seen this proto picture before? It's from beep magazine, mentioned in this video (around 14:40).
The maze has two different colors, the top bar showing the enemy's name and HP is different than the final game. Myau doesn't have HP (maybe it was dead?), and the words in the left side seems different than in the final game besides the first one. It also seems like the enemy name is only dragon instead of red dragon.
That seems to cover it. The battle menu is in a different order and one word is different. Personally I think the x1 is clearer than the multiple HP stats they changed it to. The artwork seems identical, apart from the palette.
True, world map is different in that picture. In this screen why would they put password and continue?
edit: actually it is in the text, they had 4 saves + password at some point, before they scrapped the password system. Kind of odd. And also the idea of having a forth planet...
In this screen why would they put password and continue?
It's possible that Continue just takes you to the password screen with the last password before you died auto-filled. Some other password-based games did that. Another possibility is that they didn't know if Sega would allow them the battery costs and kept both save systems in until it was decided.
The multi-color dungeons are also really interesting to see. I'm guessing they removed it to free up the colors for the enemy graphics, but it's amazing how just the few extra colors adds so much depth.