This isn't quite before my time but there are plenty of games I haven't played yet here. After some consideration I went with Japan.
Faves from this year:
1941: Counter Attack - ARC (Capcom)
Actraiser - SNES (Quintet)
Adventures of Lolo 2 - NES (HAL)
Air Buster: Trouble Specialty Raid Unit/Aero Blasters - ARC (Kaneko)
Akumajou Special/Kid Dracula - NES (Konami)
Alex Kidd in Shinobi World - SMS (Sega)
Aliens - ARC (Konami)
Balloon Kid - GB (Nintendo & Pax Softnica)
Batman - MD (different from NES ver., Sunsoft)
Bomberman - PCE (Hudson)
Bonanza Bros - ARC (Sega)
Burai Fighter - NES (KID)
Castle of Illusion - MD (Sega)
Catrap/Pit Man - GB (Asmik)
Chip 'n Dale: Rescue Rangers - NES (Capcom)
Columns - ARC/MD/SMS (Sega ARC & MD/Sega R&D 1 SMS)
Crack Down - MD (arc port, Sega & Sage's Creation)
Crystalis - NES (SNK)
Devil's Crush/Devil Crash - PCE (Compile)
Downtown Nekketsu Koushinkyoku: Soreyuke Daiundoukai - NES (Million)
Dr. Mario - NES
ESWAT - MD (different from ARC & SMS ver., Sega)
Elemental Master - MD (Technosoft)
Final Fantasy III - NES (Square)
Fire Shark - MD (arc port, Toaplan)
Gaiares - MD (Nippon Telenet)
Gargoyle's Quest - GB (Capcom)
Ghostbusters - MD (Compile & Sega)
Gradius III - SNES (arc port, Konami)
Gremlins 2: The New Batch - NES (Sunsoft)
Gun Nac/Gun-Nac - NES (Compile)
Hammerin' Harry - ARC (Irem)
Hellfire - MD (Toaplan & NCS)
Jackie Chan's Action Kung Fu - NES (Now Production)
Kickle Cubicle - NES (ARC port w/ various differences, hub map in JP ver., Irem)
Kung Fu Master/Spartan X - GB (different, Irem)
Liquid Kids - ARC (Taito)
Little Nemo: The Dream Master - NES (Capcom)
MUSHA/Musha Aleste: Full Metal Fighter Ellinor - MD (Compile)
Magic Sword - ARC (Capcom)
Mega Man 3 - NES (Capcom)
Mercenary Force - GB (Lenar)
Mercs - ARC (Capcom)
Metal Gear 2 - MSX (Konami)
Ninja Spirit - PCE (1988 ARC port, Irem)
Nintendo World Cup/Nekketsu Koukou Dodgeball-bu Soccer-hen - NES (Million)
Out Zone - ARC (Toaplan)
Parodius Da! - ARC/NES (Konami)
Rampart (Japan, Konami ver.) - NES (various differences, original by Atari Games)
Rod Land/Rod-Land - ARC (Jaleco)
Rolling Thunder 2 - ARC (Namco)
S.C.A.T.: Special Cybernetic Attack Team/Action in New York/Final Mission - NES (Natsume)
Shadow Dancer: The Secret of Shinobi - MD (different from arc ver., Sega)
Shadow of the Ninja/Blue Shadow - NES (Natsume)
Super C/Probotector 2 - NES (Konami)
Super Mario World - SNES (Nintendo)
Super Star Soldier - PCE (Inter State)
Target Earth - MD (NCS)
Teenage Mutant Ninja Turles II: The Arcade Game/TMNT 2 - NES (arc port w/ some differences, Konami)
Thunder Force III - MD (Technosoft)
Whomp 'Em/Saiyuuki World 2 - NES (Jaleco)
Wonder Boy III: Monster Lair - MD (arc port w/ some differences, Westone or Aicom)
Bubble Ghost - GB (some differences, Opera House, originally by ERE Informatique)
Chip's Challenge - DOS etc. (1989 Lynx port, Epyx)
Dangerous Dave - DOS (John Romero)
King's Bounty - DOS (New World Computing)
King's Quest I VGA - DOS (Sierra)
Klax - MD (arc port?, Atari)
Loom - DOS/AMI/ST/MAC (Lucasfilm Games)
Maniac Mansion - NES (update of the 1988 JP ver., Realtime Associates)
Prince of Persia - AMI/DOS (1989 AII port, Broderbund)
Rampart - ARC (Atari)
Rise of the Dragon - DOS (Dynamix)
Smash T.V. - ARC (Midway)
Star Control - DOS/AMI/Amstrad CPC (Toys for Bob)
Stunts - DOS (Distinctive Software, Canada)
The Secret of Monkey Island - DOS (Lucasfilm Games)
Spider-Man/Spider-Man vs. Kingpin - MD (Sega of America)
Paradroid 90 - AMI (Graftgold)
Snake Rattle n Roll - NES (Rare)
Solar Jetman - NES (Rare)
Solstice - NES (Software Creations)
Turrican - AMI etc. (Factor 5 AMI/Rainbow Arts C64)
