Dragon Quest 1 SFC / GBC Magic Armor heals 1HP per 4 steps / Magic Armor Heals 1 HP per 2 steps Fairy Flute is 6 steps South of the hot spring / Fairy Flute is 3 steps South of the hot spring Repel works for 128 steps / Repel works for 64 steps SFC starts with slightly less HP on average / GBC starts with slightly more HP on average
Dragon Quest 2 SFC / GBC Mage Staff, when used in battle deals 16-24 Fire Magic damage / Mage Staff, when used in a battle deals 16-20 Fire Magic damage Water Cloth reduces Fire Magic and Breath damage by 50% / Water Cloth reduces Fire Breath and all Magic damage by 50% Loto Armor reduces Fire Magic and Breath damage by 25% / Loto Armor reduces Fire Breath and all Magic damage by 50% Devil Tail doesn't properly Curse, as in no negative affects / Devil Tail will curse with full negative effects, can't remember what they are Seed differences: 6 Strength, 4 Mystic Nuts / 7 Strength, 3 Mystic Nuts Monster drop differences: Metabble drops a [Dragon Potion - acts like a save point anywhere, but loads at the last normal save point] / Metabble drops a Magic Hat, the best hat in the game, allowing access to it BEFORE the Cave to Rhone Double Attack differences: Falcon Sword and enemy monster Attack Twice abilities will not retarget if the intended target dies on the first hit / Falcon Sword and enemy monster Attack Twice abilities will retarget if the intended target dies on the first hit Repel keeps enemies away for 128 steps / Repel keeps enemies away for 64 steps Stepguard turns off when everyone exits the damage tiles / Stepguard works until the party moves to a new floor
One last one: GB spell costs are lower in both games, by a small margin for some spells, by a large margin for others, anywhere from 20-75%. Some spells are the same cost.
(GBC is basically made easier in all regards so it depends if you prefer the SNES or GBC grafix) ---