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SpaceGem4k (

By Gavin Murrison, submitted on Feb 28, 2014
Min JRE version:
This game was submitted in the Java4K 2014 Competition.
Source code available! Show source code

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A tribute to SpaceChem.

You have recently become the proud owner of the only Gem Embedding Machine in the whole world! This machine could make you and your jewellery business rich beyond your wildest dreams! Now if only you can figure out how to operate this complicated machine...

This is a tribute to the fantastic SpaceChem game by Zachary Barth (founder of Zachtronics Industries). Zach was once quoted as saying that SpaceChem would have sold many more copies if it had been about gems instead of chemistry!

Zach, thanks for inventing SpaceChem. The world is a better place for it. :-)


Use your mouse to click on the toolbar at the top, to select operations. Click on the grid to place an operation in a grid square. The always-moving 'Waldo' will obey every operation that it passes on the grid.

Key to the operations:

W = Waldo start location. The Waldo will always start from this operation and move towards the left.
(blank) - Use this to erase unnecessary operations from the grid.
U = Move up
D = Move down
L = Move left
R = Move right
T = Take gems. The Waldo will grab hold of any gem in this grid square, and move it and any joined gems around the grid.
P = Put gems. The Waldo will drop any gems that it was holding, and leave them at their current location on the grid.
1 = Call in some gems into Input One Zone (the purple zone in the top-left corner of the grid).
2 = Call in some gems into Input Two Zone (the cyan zone in the bottom-left corner of the grid).
O = Send out any gems in the Output Zone (the yellow zone in the top-right corner of the grid).
+ = Bond any gem held by the Waldo with any neighbouring gems (above, below or to the side of the Waldo).
- = Break bonds between the gem held by the Waldo and any neighbouring gems.

Work your way through seven levels of increasing difficulty. On each level you need to send three gem clusters to the Output Pipe, in exactly the desired configuration shown at the far right!

Do not allow the Waldo or any gems to hit the boundary of the grid! Do not allow any gems to collide with other gems! Do not call in gems over other gems! Gems that are sent out must match the desired pattern exactly, and lie in the output grid in the exact same location as shown in the pattern! If you make any of these mistakes, the GEM machine will reset itself, and blindly attempt to repeat the operations from the beginning...

User Comments

Total 2 comments:

#1 By Harm Boschloo Mar 8, 2014 at 03:20:30
This seems like a fun game to me, but I just can\'t figure out how to play it. Any tips?
#2 By Gavin Murrison Mar 22, 2014 at 14:46:51
Hi Harm. Sorry for the delay in replying - I have been out of the country for a few weeks. The instructions above are comprehensive, and should tell you enough to be able to play (although this is quite a complex game, just like the original SpaceChem). Essentially you need to pull clusters of gems into the machine, bond them together with other clusters of gems, and move the resulting cluster to the output area. This mimics the SpaceChem game exactly, but if you have not played that game it may be difficult to grasp the concepts.

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Source code

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