I am thinking of doing a playtest survey for my game in the future and I was wondering, what kind of things do you want look for in a playtest?

Is it stuff like how the player interacted with the mechanics? How long did the player play for? Did the player played the full game? This could be useful info for both people who host playtests and people giving feedback to other games.

 What do you think about it? What kind of information would you want from a person who is playing your game? 

1. How easy is it to understand the game mechanics? Does the player need to get directions from the project page, or can they infer it 100% from the game?
2. Can the player easily break or softlock the game?
3. When are points in the gameplay that the player is confused? How quickly can the player resolve their confusion?
4. Are there any points when the gameplay becomes repetitive?

1- What prompted them to download and play the game?

2- When did they stop playing the game, and why?

3- What was the most satisfying moment in the game? Why?

4- What was the most disappointing moment in the game? Why?

5- Which character did you like/dislike most?

I'd like to know these from playtesters:

1. Can they grasp how to play my games? without me explaining to them that is.

2. Can they figure out the goal of my games?

3. Are they having fun?

4. Can they complete my games?

I think your focus will depend on how you'll approach your development.

There's the rapid prototype method where you build small itterations and get regular feedback on what was fun, what was jank, and opportunities for potential. 

(You'll want a wide variety of playtesters who want to feel clever at giving you unique well-detailed reports. The appeal of an advice-giver being considered noteworthy as they stand out from their peers can be incentive enough to want to give you value.) 

If you follow a waterfall model for your project and have a solid idea of exactly what you want to craft, feedback is more observational and scientific.

(You'll have to devise all the components of your project yourself: UX, sound design, use of mechanics and how many times a player will attempt something before they give up, etc... and measure each one in a metric that's meaningful to you. You can get reviewer engagement if they feel that they've been given a challenge. And a 'try to break this game within a stated limited scope' can be just the thing if you believe your potential playerbase will all be trolls.)