First fan of the comics and following on twitter Gonna have to be critical ;)
Lose conditions:
1. When you die you want to have a menu that offers to retry or quit. You have one for the you win but not if you die.
Monsters:
Spiders: Move roughly the same speed as the player or maybe a little less. you can run circles around them and avoid damage easily. maybe increase their attack & movement speed to making them more of a threat
Cobra:
Stationary, fires projectile that can be easily dodged with no effort.
Suggest increasing projectile speed, diagonal spread projectiles at random intervals and also making the projectile look more menacing also make the snake move in different directions and maybe create a barricade as it moves to block the player.
The Boss
Caught me off guard not gonna lie that charge perfection but its a one trick pony once you know what it does you can just dodge past.
Bugs: You can run out of energy and it wont recharge.