Congrats again. What intrigues me the most, is the choice of different graphic style for the title logo, along the three versions which potentially can produce almost the same charset graphics.
Viewing post in Carcer (Commodore 64, Commodore Plus/4, Atari 8-bit) comments
I'm afraid the reason behind it might not be as intriguing/interesting as you expect. The C64 version uses multi-colour text mode for the logo. Since Atari does not have this mode (at 320x192 it is B/W anyway), and does not support more than 128 user-defined tiles, I opted for a simpler logo.
To my knowledge Plus/4 does not have multi-colour text mode either (only in bitmap mode; please correct me if I'm wrong), so I just went with the Atari version and a simple colour gradient.