Hmmm; are there even 10?
I no particular order; I really don’t play games very much these days, but did actually play these.
Signed up last night to talk about music - first ever post ‘video games’! 
Unreal Tournament
Half Life 2
Sonic the Hedgehog
Portal 2
MarioKart
Witcher 3
Breath of the Wild
Fallout 4
Horizon Zero Dawn
Tomb Raider
Afterburner. I wasted many many quarters on that game when I was a kid.
Lode Runner
Street fighter II
Another world
Speedball II
Duke Nukem
Lemmings
Max Payne
Tomb Raider II
N
TrackmaniaRimworld
Zelda BOTW
Zelda minish Cap
James bond nightfire (multi memories)
Goldeneye 64
Ms. PacMan
Galaga
Dig Dug
Tempest
Joust
** end of list **
Towerclimb
Thumper
Stephen`s Sausage Roll
The Wittness
Return of Obra Dinn
Hexcells, Hexcells Plus, Hexcells Infinite
Spelunky classic, Spelunky hd, Spelunky 2
Hotline Miami 1(not 2)
Undertale
Towerfall Acension
edit: can’t belive i forgot celeste. great game.
Excellent lists in this thread!
I think I’d need a top-50 list to fit my absolute favorites.
I’ll probably miss a lot, but I’ll put something rough together here 
Not a rigid top-10, but definitely a group of my favorites off the top of my head, and not necessarily in order. Missing a LOT of favorites.
1 . System Shock Series
2. M.U.L.E.
3. Archon
4. Ultima Series (Pagan is my favorite.)
5. Chrono Trigger
6. Zelda Series
7. Mario Series
8. Doom Series
9. Hollow Knight
10. Castlevania Series
That covers very little. Doesn’t touch Amiga games, many C64 favorites, Arcade favorites, fighters, etc. Metroids.
Riddick: Escape from Butcher Bay, Quake Series, Samurai Shodown Series, etc.
Too many excellent games over all systems. PC Engine has probably 50 favorites on its own
Some modern ones like Dishonored and Prey, and tons of Indie games like Fez, Hyper Light Drifter, etc. deserve mentioning too.
Robotron
Money Puzzle Exchanger
R-Type Series
Ghouls n Ghosts
Dimahoo
I forgot to add Terraria. I run a server for my family, and probably have 1000 hours in it building advanced worlds with my daughters. Rail systems above, below ground and in sky, tubes from bottom to sky, and crazy buildings everywhere, hanging sky gardens, etc. It’s interesting to watch the evolution since we all play at different times.
In no particular order:
I’m not much of a gamer.
I regret not including Jumpman Jr in my list.
I feel like in some ways its hard to make a comparison with story and competitive games, eg. I’ve played counter strike for 10 years on the same maps same guns for 1000s of hours, how does that compare to a story game that I only play through once. Its almost like comparing watching football to watching a movie
Super Dodgeball (NES)
Kerby’s Pinball Land (Gameboy)
Sonic Spinball (Genesis)
Grim Fandango (PC)
Quake 3 Arena (PC)
Power Stone 1 or 2 (Dreamcast)
Soul Calibur II (Dreamcast)
Shenmue 1 (Dreamcast)
GTA: San Andreas (PC)
Psychonauts (PC)
Wii Play Tanks (Wii)
Broforce (PC)
Okay, 12. I could certainly list more… but I can’t remove any from this list.
a lot of good memories in these lists, too many for me to choose a top 10 as i could prob agree with anyone’s list depending on the day of the week…
that said, i’m a little disappointed nobody has mention Turrican 2
this thread give the average age of ppl on this forum ^^
Nobody saif Left 4 Dead 2 ?
For me:
Left 4 Dead 2
Satisfactory
Hunt Showdown
Rocket League
Team Fortress 2
Tribes 2
Global Agenda
Shootmania Storm
Binding of Isaac
Rogue Legacy 2
Online games are better 
Wow. Old memories surfacing…
Same goes for me when people choose any part of the series other than the first one that came out 
Dark Souls
Fallout: New Vegas
Xenoblade Chronicles 2
Rocket League
Elder Scrolls: Skyrim
Paper Mario: The Thousand Year Door
Tales of Vesperia
Half-Life
Beneath a Steel Sky (original)
Dragons Dogma