I have noticed a trend in Ludum Dare themes, there are two categories that I have identified, these are descriptive themes and meta themes.

Descriptive Themes

• Roads (LD13)
• Caverns (LD15)
• Islands (LD17)

These themes have no design requirement, they just require you to have your game themed with this setting.

Meta Themes examples

• Delay the inevitable (LD50)
• Stuck in a loop (LD47)
• Keep it alive (LD46)

These themes are more of a design constraint for the game designer. The challenge of this type of theme is to create a game satisfying some requirement, such as having something inevitable eventually happen or being forced into a loop.

Which ones do you prefer?

Most recent LD themes have been meta themes, except "Unstable" which is a bit of hybrid. For this reason, I would like to see more descriptive themes like "Garden", "Ocean", etc.