Similar for me in my early teens. I used an Australian machine called the Microbee, https://www.microbeetechnology.com.au/classic-plus-kit-compu...

A clever friend of mine wrote BASIC games that he sold back then. I think they had a bit of Z80 assembler built into it too.... Can't remember what names of them were though.

The 'hires' graphics mode (511*255, monochrome) were encoded into sprites. There were only 128 characters from memory. There were all sorts of tricks to try and get around that issue.

The best games used the sprites plonked into char positions.