Interactivity Testing Feedback Questions

I've been writing an interactivity testing questionnaire in advance for gathering feedback from people who will test the game for us. The questions I have settled upon are as follows:

Questions asking the user to rate the game on a 1 to 5 scale:
How enjoyable was the game?
How difficult was the game to understand?
How difficult was the game to play?
How much did you like the game's graphics?
How likely are you to purchase the game?

Short answer interview questions:
What did you like about the game?
What did you dislike about the game?
What things did the game bring to mind?
What would you change about the game?

The key things I am aiming to draw from the feedback are how well the user understood the game play (controls, elements, challenges) and what they find valuable about the game design (what works, what doesn't, what's enjoyable). It's important at our current stage to find out how explicitly we need to instruct the player as opposed to letting them work things out themselves. Currently we are debating over the inclusion of tutorial stages; whether or not the elements need explicit introduction and explanation, or whether the game is intuitive enough to allow the player figure things out without instruction. Related to this is training the difficulty level of the game to avoid the game being either too frustrating or too straightforward.

Asking the user what they liked and disliked about the game is a means to find out which elements work best and stand out in the game design and which ones need to be reworked. Likewise for the graphics; whether they are appropriate for the game or should be reworked. Asking "what things the game brings to mind" is a way to find out what really stands out about the game, in relation to either other games, genres, mediums, or even concepts, and to see if our target of a uniquely intriguing puzzle platformer is inline with what users actually feel about the game.

Asking how likely the user is to purchase the game is a measure of how much value they place on the game experience and whether it is good enough to hold their interest. It will also help to assess the most appropriate audience for the game, being those most likely to purchase it.

Obviously the most important element in regard to test feedback are the levels used in the testing; they should be designed primarily to introduce the player to elements whilst also keeping a suitable challenge level.