Fun! Your next attacks shoots bombs + regenerate your energy to full + shoot 4 bullets x times is a bit too powerful. The cards that don't cost energy are just very strong in general because you redraw immediately.
I don't love the cooldown system. Having to wait to play cards feels bad. I'm not sure that cooldowns are even necessary when you already have to wait to restore your energy. Feels like you could remove energy or remove cooldowns and the game would be more fun.