Astronomy Puzzle 8

Play the traditional/classic puzzle-8 game (also known as sliding tiles or slider-puzzle, or puzzle-9) with enchanting galaxy and space themed images, right on your phone or tablet. No physical game board to carry around and there are many pictures included. All levels are free to play with no In App Purchase.
The game rules are simple and this mobile version can be played simply with tap and touch interface. The player is presented with 8 tiles arranged in rectangular grids containing a picture. The tiles are then scrambled so the pictures looks out-of-order in the grid. One of the 9 slots is empty (has no tile), and you can slide a tile that is adjacent to the this slot to solve the puzzle. The goal is to unscramble the tiles and put them back in order (in the correct places), so that the tiles form the original/complete/unscrambled picture.
But you need to think ahead and sometime backtrack your moves. The puzzles can be frustrating (or addictive) in that you might feel that you're very close to the puzzle's solution, yet there's that just one tile in the wrong position. Sometimes the correct tiles are adjacent, yet swapping them is not easy because the tiles can only be moved to the empty slot. And sometime moving just one tile can take dozen or more moves to put in the correct slot, while the game ends up with even more tiles in the wrong slots.
Complete with the fewest move and as fast as you can. Your time is recorded so you can replay to improve your best times.
There are over 30 breathtaking out of this world, galaxy and outer space images with subjects ranging from planets, spacecrafts, satellites, stars, nebula, and rockets. Puzzles are randomly generated so you won't get bored. Unlock all these epic space pictures and admire the beautiful galaxy.
A bit of background: Because of its simplicity and elegance, Puzzle 8 game mechanic and it's counterpart, the puzzle-16, have been traditionally used as tools in the field of Artificial Intelligence (computer brain) to test new AI algorithms. There are various AI algorithms that can solve the puzzle, such as A* (pronounced "a star") or depth-first-search.
CREDITS
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Images courtesy of/images credits: NASA, JPL, STScI, ESA, SOHO (full credits provided in game and in the following link: http://permadi.com/apps/puzzle-galaxy/credits/).
Disclaimer: This product is not endorsed by NASA, JPL, STScI or other credited entity/organization. The publisher of this app is not affiliated with the credited entity/organization.