Schein (Steam key/Region free).

http://store.steampowered.com/app/321920/
Schein is an award-winning, puzzle platformer that tells the story of a father who enters a mystical swamp in desperate search of his son. As he becomes enveloped in darkness and begins to lose hope, a wisp appears, offering him guidance and her magical power: a light that reveals hidden worlds.

Use your wits and light to conquer mind-bending puzzles and defeat deadly beasts. Can you save your son in what’s possibly the trickiest platformer you’ll play all year?

Key Features
Explore three hidden worlds, each with its own art style and dangers, using magical lights unlocked throughout the game.
Solve perplexing, occasionally maddening, puzzles and master challenging platforming action.
Use your intellect and reflexes to battle deadly bosses.
Immerse yourself in Schein’s story as it unfolds in fully synchronized dialogs accentuated by leed:audio’s atmospheric soundtrack.