hm, cant do a video right now. ill try to elaborate.

Its as though the cassette broken? I dont think it is cause itd be much worse, but then again, this is why im here. Whenever i shift into the smaller 4 gears (size wise) the bigger 4 can move together separately from the smaller 4. By moving i mean spin slightly. kind of like the tiny amount of play you get right before your cassette clicks to the next [gear?]. It wont click into a new spot, but it has about the same amount of play. i can hear something in the back of my bike making a sound when i hit a bump, which i believe this is it since ive looked and made sure everything else is tight.
anyways, to sum it up in simpler words, picture the whole cassette. the chain is on the smallest cog. i can move the 4 biggest cogs (by move i mean spin as though it was moving with a chain on it) a tiny amount. The smaller 4 cogs wont move when i move the 4 big cogs which makes me worry.

I hope that kind of gives a picture. ill try to get pictures or a video soon, if this didnt help