Quell: Memento

In Quell: Memento the player must traverse a small maze with a blue orb. In each move, the player flicks the orb in one of the four basic directions, and the orb will not stop until it hits an obstacle -- you cannot change directions during its movement. The goal of the game varies a lot: in earlier levels, you have to collect pearls scattered around the maze; later, you might have to light tiles by passing next to them, avoid spikes, or illuminate targets using beam-emitting orbs.

Later levels have multiple orbs (which may have different colors, and some of which may be sacrificed), destructible ice blocks, and other assorted game mechanics. The levels are not timed, but in order to get a 'perfect' rating you must match the minimum number of moves determined by the designer's solution. If you lose all your orbs, or reach a position from which it is impossible to win, you can quickly restart the level -- most of them can be solved in under 30 moves.

Additionally, each level has a secret gem that you can uncover by breaking specific wall tiles (often not found during the standard solution). Moreover, some levels have secret exits to extra "timekeeper" levels, with new goals and 'timepieces' to be found. As you solve the 144 levels (plus the bonus ones), the main character recovers memory fragments revealed during short voice-overs.