The core is very tough, I like the concept and how you implemented it.
Toughness factor + 1 
An even more awesome core could be a moving labyrinth, please include such a core in the future!
I would like to know if anyone had any trouble understanding what was going on, if their are any bugs, if it runs well and if you think that it's too easy or hard. Or ugly.
I understood perfectly what to do, the title and idea is brilliantly done.
The green lines in the background were psychedelic, and attacked my eyes. My eyes suffered then. ;(
The player character is a bit difficult to see when moving, and often I didn't notice when projectiles were heading towards it. Maybe it should be as visible as the core, or at least more visible than the enemies.
That's details though, in the end your game has a lot of potential.
Developer
