[bjt12345]

I never figured out how they did the turtle graphics in this game. The C64 didn't have whole screen bitmaps, you could either use sprites or user defined character sets, neither of which made this straightforward.

And the loading screens were also amazing, particularly for tape loading.

[steve_taylor]

The C64 does have a couple of bitmap modes. The Last Ninja uses mode 3, which is multicolor bitmap mode. It occupies 9000 bytes including pixels (8000 bytes) and color RAM (1000 bytes).

[smcameron]

The TI99/4a version of the Logo language which has turtle graphics used user defined characters to implement them. There were only (I think) 128 user definable characters, and when the turtle graphics had redefined all of them to create its output, it gave the user a message, "out of ink".

[vidarh]

As others have said, the C64 does have bitmap modes, though it's understandable not being aware of it as they weren't that commonly used for games since it was often easier to use user defined character sets as tilesets if you had repetition.

[EvanAnderson]

You might be thinking of another system (like the NES, perhaps), because the C64 has 160x100 and 320x200 bitmap modes.

[hcs]

Even on NES a lot of games use CHR-RAM so arbitrary bitmaps are at least possible, though only a small part of the screen is unique without some rarely used mapper hardware. Zelda and Metroid mostly just use this to compress the graphics in ROM, Qix is a simple example with line drawing, Elite is an extreme one.

I made a demo of the Mystify screensaver using the typical 8KB CHR-RAM. Even with a lot of compromises it has pretty large borders to avoid running out of unique tiles. https://youtube.com/watch?v=1_MymcLeew8

[EvanAnderson]

Elite is my go-to example for madness in a tile-based grapgics system. Watching the CHR-RAM in an emulator while Elite is running is mesmerizing.