Is there a deterministic winner?
This is an important question to consider since, especially for multi-player games, it becomes very dull to play if there is a deterministic winner. Even the simplest barebones model that has the game mechanics would be sufficient to answer this question, and I believe that if the answer is that there is a deterministic winner, then the game may need to be modified.
Does the game run smoothly?
A slightly more robust prototype would be good to answer the question of whether the game runs smoothly or not. If there is low friction, the players may better enjoy the game and with a smoother running game, there may be more retention and play of that game.
Is the core idea/experience enjoyable for the user?
This is a key question since the core idea is what is built off of in every other aspect of the game, so if it isn’t enjoyable, then the players may never come back again. A very lo-fi prototype could work for this layer of testing, and if the finding is that the core idea and experience are enjoyable for the user, then your game will likely have a lot of traction.
