Very enjoyable. I got a normal difficulty run for my playthrough. Presentation was top notch! Gameplay is lacking a bit. I'd say either go full Vlambeer on the attack and make it full-auto and with a bit of knockback, or do something more creative with the fact that you are throwing cards (which I found very satisfying).
The room on the right for the boss fight kind of lets you cheese the fight a bit, just duck into cover when he shoots you and then continue blasting.