Dodging is even harder.remember you can dodge, running is not your only option
I was playing games in early 80's. The type of games back than was Atari, Nintendo, Super Nintendo. Most of these games did not run very fast and many were RPG which definitely were turn based. Today's generation has grown up with games on mobile devices and mobile phones that take extreme dexterity. I can type around 80wpm but on mobile I am slow as molasses. Different generation and the games you play now on normal/easy mode would of been HELL mode if we had it back than. So please don't compare the generation and call the game easy. It's easy for you all that grew up and played on this generation of games..
1. Grew up on games like the text based Infocom
2. ASCII games like Rogue dungeon in DOS
3. Point and Click games
So trying to play a game that has me trying to control dodge and direction by keyboard is too much for my coordination. Stage 2 was hell mode for me and 3 was damn impossible mode. An adult game should not alienate anyone by being too difficult of an action game. The moves like the jump than drop down really fast took me many tries to get past that door as I DO NOT have the hand eye coordination for them type of moves.
Best way would be to take the health level of the previous level and do a multiplier or divider on difficulty. If person barely survives reduce the number of enemies and if the person walked through it practically increase it this way it would stay challenging for all levels of players. Divide could be done a few ways. (slow enemy movement down on the counter on how fast they attack or move as well as add collision to the bullets shot by the plant enemies so can use platforms to stay out of the fire of the plant while fighting the flying mob)