Fun and addicting! Game has a lot of polish and pizazz to it: love the little touches like smoke trails for the bullets, coin magnetism, blood splatters, etc. Felt like the slo-mo could use a bit more of a signifier that it's on, like a full-screen blue blur/vignette effect or something, since I'm not able to take my eyes off the enemies in the center to look at the mana bar tucked all the way in the corner. Could maybe use some sort of indicator when another shot is ready to be fired. Also you might want to make the 'next wave' more prominent and different of a button than the 'replay' to give it the focus it deserves. All-in-all, the gameplay is simple and intuitive with some interesting variety that makes you want to keep going blasting away, bit-by-bit.