Most of these games aren't too long, with Ys 4 and Lucienne's Quest the longest at ~20 hours.
NES: Power Blade, Willow, Metal Storm, Dragon Fighter, Gun Nac, Crystalis, Goonies 2, Jackal
Turbo/CD: Ys Book 1 and 2, Ys 4 (fan translation), Xak III (fan translation), Lords of Thunder, Legendary Axe, Exile
Master System: Wonder Boy III
Genesis: Thunder Force 2-4, Ranger X, Shinobi III, Saint Sword, Landstalker, Crusader of Centy, Castlevania Bloodlines, 2 Crude Dudes
SNES: FireStriker, Run Saber, Space Megaforce, Magical Quest starring Mickey Mouse, Brain Lord, Neugier (fan translation)
3DO: Lucienne's Quest, Return Fire
PS1: Tail Concerto, Internal Section, Gunners Heaven
Saturn: Tryrush Deppy, Shienryu, Battle Garegga