Suggestion about single-player:
Each task has a certain 'required time' value (for example 60 - 100 for crafting -> see crafting menu). Is it possible to include a multiplicator for the required time in sandbox menu?
For me it feels a little strange to be able to dig like 20 graves or build up walls in a few seconds for example. With the multiplicator players would be able to generate more/less time-consume per task and make gameplay a more realistic factor, or more arcade-style. For example: If you go with realistic values you'll need 10-20 mins to build up a wall and you have to secure the environment for zombies first. Its about time planning and strategy.