As a fan of roguelikes, I liked this a lot! A very polished experience, though I was hoping for a boss fight at the end :)
I really liked the details like the ghost trail for the disks and that frozen enemies take damage from spikes.
One suggestion is to make the rarer power-ups more likely to appear or even guaranteed after a certain point. I finished a run with only the basic power-ups, though I was more than strong enough by then.
Really nice work!