1. No Extended Playing Sessions.
Voice Control is a great tool for quick and simple actions, so therefore Players don’t want to be sat for an hour playing an entire game. Of course they can have the option to do so, but the majority of users will only want play for a few minutes, an example of this is Candy Crush.
You play a single game until you run out of lives and can’t play more so you go and do something else, The same should be with Voice Controls. Developers want Players to play as much as possible, but on a device like a Home Assistant? That’s not feasible nor a logical approach in the long term usability.
2. Invoke Commands need to be simple
Players should be able to accomplish lots with very little, making Players have long sentences will require more invoking guidelines for your program. Keeping the commands simple to something like: “Build a farm” is essential for reducing the risk of the user becoming confused with what to do.
"Alexa, Build a Farm."
3. You don't need big lists
We love big complex games, many lean on predefined concepts for things like Controls and Menu Options. However on a device with no screen or interface to read, complexity is your enemy. You cannot have a list of more than 2-3 options, because the everyday user will most likely forget the first options when you get past the 4th. Therefore having the device read out simple words like Play, Options and Exit are more than enough for a menu.