If you think a game should be higher or lower in ranking, then upvote or downvote it. If you don’t see a game on the list that you think should be on the list then create a top level reply with the name and system.
Pokémon Crystal is just shy of your 25 year threshold depending on what month it was released (it came out in 2000 in Japan), so I’ll say Pokémon Yellow or Polémon Gold and Silver. We can sit here and nitpick about which is the best, but Red, Blue, Yellow, Gold, Silver, and Crystal were all amazing.
Might and Magic III
F19
B-17 (intellivision)
Pitfall
Zork
Myst
Gauntlet (arcade 4 person game)
missile command, arcade
Wonder Boy: Monster Land, Arcade, 1987
Super Mario Bros 2, NES
sonic 3 and knuckles, Sega Genesis
Shinobi 3, Sega Genesis
IK+ (International Karate plus), Amiga, 1987
Bubble Bobble, Arcade, 1986
Resident Evil (1996)
Street fighter 2 - hyper fighting edition (arcade).
Played this every day after school for years as did a huge portion of my school.
Ultima IV - Quest of the Avatar (C64)
UFO (or xcom) - enemy unknown.
Little Big Adventure 2
Death Rally, 1996 (PC)