Just currently learning more about Metroidvania which see to be most popular genre .
Example of a few below:
Metroidvania
Tower Defense
RPG
Rougelike
Bullet Hell
Turn-based
Real Time Strategy
Puzzle Game
Can you think other components which makes genres unique ?
The game mechanics for sure.
IMHO genres are a little bit artificial. Is Rimworld a tower defence? I could argue, yes.
There are so many cross over, same as in music. I hate that every band must fit into a genre.
Yes , but generally their ancestors for example “age of empire” , a bit defined it . Strategy right ?
It’s open for discussion. In a different thread of mine, there was the conflict, if “Little Computer People” is the ancestor of the Sims. I would argue, yes.
But Rimworld has some game mechanics from LCP and Sims, too. Is it now a Life Sim? It has mechanics from Minecraft, too. Is Rimworld an open world survival like Minecraft?
IMHO Genres are too constraining to define a game.
I was more about what makes certain genre what they are recognised for , rather then specific games .
Like in music it’s so many now but basic would be classic , cinematic, blues, rock , metal , jazz anything more would be inherent.
All i really know about the genres is JRPG v.s. WRPG.
When i think of RPG i usually think Dragon Quest or Final Fantasy though.
(Chrono Trigger, Breath of Fire, and Golden Sun also count)
Certain times the music styles and art styles also define genre stuff, e.g. retro v.s. modern genre,
like most pixel art games, then theres the HD2D graphics, which i somewhat consider a genre.
Ig a lot of it is subjective, anyone agree?
Yes subjective .
But also if you building game you break it down into components and mechanics via nodes , signals , art and this pretty much would be good guidance when makes a generic learning projects . 
When thinking of survival game I know will need items , enemies which attacks , health , resources as hunger , thirst , sleep . So this defines that
Aye, indeed—its kinda basically “where the matrix begins”, we could break it down by all mechanics, by regional styles (Japan style or Western Style for a basic example), by length of the game, etc. i would say that the main game mechanics are probably the most important part of what makes it this genre and that though.
Ok let start with camera view types
Top-down (Strategy , Tower defence, RPG )
Side-view ( Platformers )
What else would be added ?
probably 1st-person view,
In 2d 
Is this be one sort of shooter ?
I would claim that genres are only important for marketing and to tag your game in steam with one.
Well , yeah at stage of release I agree .
For learner and mess around would make sense to know ingredients to know what can I mess with in kitchen .
Well from my perspective : how to make camera behave , will it zoom in out based on action , player input , will be fixed ?
Control : UI and touch/ mouse interaction .
Controller with vibration on damage etc .
More focus from this side what components are possible and try figure how to make them and use . Not be only limited to copying other games , or necessarily play through so many , but rather set a this basics .
Many times was mentioned coyote jump and I don’t know what it is , but find out it’s basically double jump with timer from first jump
think like the old Commodore 64 RPGs, a 2d shooter could be possible too tho—i got a lot of (sometimes bad, think double decker couch hahah) ideas
Never had one of those 
what could you run on those ?
lol, theres quite a bit of arcade-like games for the C64 i cant even count,
i mostly had the game “Wizardry I” on my mind to be honest though.
I wanna say there was a sort of mock 3d 3rd person perspective game for atari that involved driving a car as well.
If you should recreate it , what would be things you do to achieve it ?
you could probably fake it with a 3d scene and a shader that limits the colors so much that it looks 2d, then lower the resolution, for the encounter scenes, etc. you could just swap to a 2d screen,
otherwise it would take so much graphic editing (in my oppinion, i am probably just being lazy tho)
Well would be more interesting to create manual drawing instead of using assets , using vertex from blender into arrays , and making meshes and LOD as go with minimal resolution to keep it close to old fashion.
I had play with some nearly and cube and it could be interesting to generate those values and store them instead of graphic resources