Well, by "modes" I really just mean graphical styles (done on the same hardware? I dunno), like how the NES has a "Mode 7" mode, and other display modes, where there's distinct differences between how a game like Super Mario Bros. 1 looks compared to Super Mario Bros. 3, or how the game called "Castlequest" ( https://www.youtube.com/watch?v=wuyiI8O6Ecc ) looks much different than them both (seeming to be in a "less vibrant" graphics mode).

Some Commodore 64 games featured graphics where it was like "specifically designed" text "characters" for "grid spaces", where your character's movement was grid based (like in the hugely popular Commodore 64 game called "Boulder Dash". https://www.youtube.com/watch?v=62lv3oFyos0 ). That reminds me of "MegaZeux" - a text-based "create your own worlds" game featuring "games" made from a series of "boards" (screens) with pre-programmed objects and also, the shining gems of MegaZeux, the vastly programmable objects called "robots" - the "heart and soul" of MegaZeux (here's a MegaZeux game that was done without much altering its natral text-mode graphical style, which is crafted after the Super Mario franchise: https://www.youtube.com/watch?v=v1B-W5tbtnk ).

One minute you could have a Commodore 64 game that was like an 80's arcade game with flashy, glossy graphics (for how they were "like that" for that time period), and then ones that seemed to give off more of a "dirty" look where colors were more flat, or where sprite art was fairly vibrant, but a little "bloated" (not nearly as "compact" - quality - as in 8-bit NES games).

I don't exactly know all of the proper technical terms here, but the gist is that there are several Commodore 64 games that look uniquely different, just like how there are many NES games with different graphical styles (perhaps even in the same mode due to different graphics artists' different styles.).