I played the prototype and as far understand the idea, it's supposed to be similar to an escape scene, such as a driving scene when bullets fly from all directions.
This is the feedback:
- First point, the turning was too slow and I took most of the damage when turning.
- Second point, the feedback on the directions was sometimes too late.
When it comes to making a game solely about escaping in bullet hell, why not?
Super Mario Bros is a game solely based on the concept of moving from point A to point B on a singular axis and what makes it fun is the things between the start and the end.
For your game, that is the case for both playabillity and fun and as far as I can see it, it's a solid 2 or 3 out of 10 on the prototype but don't be discouraged by it as it can be improved by adding things in the middle of the journey, a change in the environment as well as bonuses or pickups.
Concept wise, I would give a 4 or 5 because I find those scenes in games fun.
This is my feedback and is based on my reactions and my first impression.