20 Challenges: Episode 1 - A feard enemy

This is the 1. Episode of a challenge series Every 3rd month will come a new episode with 20 new rooms and settings.

How will this challenge work? You get 20 one screen rooms where you has to kill all enemies. If you die you will set back to room one (or checkpoint). There is no backup power up but you get the possibility to buy every 5th room a new mushroom for coins.

Each episode will be released with an optional retro achievement set for bonus content https://retroachievements.org/game/29846