Art and music direction are flawless. hat mechanic is good, encourages you to take a leap of faith when you're vulnerable. I love the trains. Shooting feels and works well, if there's one mechanic I'd love to see, it'd be a dash.
I've had two instances where I've been killed during on-kill slowdown. If the camera doesn't push far enough it's possible to dodge incoming projectiles, but on those occasions I didn't see the projectile due to closeup.
Every now and then too much is happening on the screen, number of enemies shooting at you, something exploding, and a close-up. I think the latter should only be applied on smaller percent of kills.
Extremely strong game, in spite of few flaws.