I learnt that there are 4 video modes as described on wiki.
I came across many games for the PC-88, like Thexder (1985), which are in the aspect ratio of 4:3 and in more than 2 colors.
I don't understand how this works and can't find a resource describing it.
My guesses are, games work like this:
- run in n-mode (160×100)
- are displayed in 640×400 but they only have 640×200 pixels ("clusters"?)
- scale a 320×200 picture up to 640×400
Thank you for your help!