Valkyrie no Bōken: Toki no Kagi Densetsu

Spatial thinking

Holding a map in your head. Play a maze game without the map screen for twenty minutes. Draw it on paper afterwards and check.

Planning ahead

Thinking three moves out. Before a dungeon, write down what you expect to need. Compare after.

Problem solving

Stuck, then suddenly not. Ban walkthroughs for one game. Give yourself a day on any puzzle before you look.