Right off the bat, I eliminated flat side down from my design for two reasons. One, the stacks of gems are too stable which leads to large holes in the stack and two, gems can land while offset by half a column requiring a snap to grid that wouldn’t look natural. Points down hexagons are much less stable: as soon as two adjacent hexagons are missing then the stack will collapse down.
Unfortunately, hexagons with points down have some problems of their own. When a hexagon lands on another, point-to-point, it is ambiguous which way it should slide into place. If they always slide one direction then the stack is going to bunch up on one side. If they slide to a randomly chosen side then the game would be unpredictable, which will drive puzzle gamers nuts. The third option is having odd rows slide right and even rows slide left (as numbered from the bottom in the image.) This follows the natural ‘S’ shape of the edge of the stack. The question is, while it is predictable, is it predictable enough to not cause aggravation? Most importantly, is it predictable enough for players to set up stack collapsing combos?
I looked around to see what other games have done and I could only find one that has a collapsing stack: Hexic HD. To my disappointment, the creators worked around the issue. The hexagons are oriented flat side down and when the stack collapses the gems fall straight down. This video shows it in action. The corners of the gems just pass through the corners of the adjacent stack. That is not the solution I was looking for, but maybe it is the only way. Do any of you puzzle gamers have an opinion on the ‘S’ shaped collapse? Could it be fun or is it just aggravating?