@DragonLoverX: Just you wait until you get to Entity! Levels 21-24 are easy, like Neko's shop easy, but Entity is about 4 times as harsh as Genu on level 20!
Someone in the forum said that if you don't fire while it is dark then it will restore your energy properly. Personally, I'd rather use up a Micro Energy Boost than stop firing or using my other skills just to risk it.
My new avi (as of 3rd April 2010), in honour of having defeated Entity on my own save file. Those who've done this too can use it freely. And before I forget... YEEEEEEEEEHAAAAAAAAAA! =]
I'm the 52nd person to get the hard badge! Woohoo! Tip: for the high level boost achievements, use Sir Colin. He's hard to control, but crazily fast and flips like mad!
 "Gold Room: Ancient Coins Mobile"){kind=icon}
 "Bloody Fun Day Mobile"){kind=icon}
 "de Blob 2 Revolution"){kind=icon}
 "Drag Box 2 Mobile Version"){kind=icon}
 "Monster Slayers (Mobile)"){kind=icon}
 "Disperse!"){kind=icon}
 "Refraction"){kind=icon}
 "Zilch Mobile"){kind=icon}
 "Primary"){kind=icon}
 "Enigmata 2: Genu's Revenge"){kind=icon}
 "Toss the Turtle"){kind=icon}
 "Gravitee 2"){kind=icon}
 "CycloManiacs"){kind=icon}
 "Dog Eat Dog"){kind=icon}
 "SHIFT 3"){kind=icon}