Visited my sis and @Nossie again after celebrating Sinterklaas at our dad's.
I played through level 1 through 7 on the "Dragon Warrior" difficulty level. I unlocked 12 Achievements, most of which the "100% on Dragon Warrior" ones, for 320 points, bringing my total to 950.
Shouldn't I have unlocked the "100% Completion" Achievements too? The name suggest they should unlock with any difficulty level. Every time I start the game, or just load a level to try to get 100%, the game asks me where I want to store my save game, so I think something isn't working quite right.