I actually didnt find the hard badge that hard, got it on my third game (still havent eaten the alien though lol). My suggestion is to save up all your health points toward the end because thats when you really need them and thats exactly when they begin to run short
I must say that the game is great but the restart button needs working on since it doesn't correct my glitches half the time.
Last level and I go behind the door and i cant go through it, it happened earlier too.