Secret hearts: 1)Behind the granny house where you start. 2)on the third screen from there, where you have to jump over the platforms, go down to the platform in the bottom left corner. 3)In the forest, on the level with two reds and two spiders, there is a heart on the small platform down below (with a red monster, be careful) 4)In the lab, in one of the rooms with the purple laser on the lowest level, go a bit past it, there's a heart. 5)In the city, with three rising and lower platforms, a bird up in the sky and a guard in a nook in lower right - there is a heart with the guard. 6)On the roof of the indie house. 7)Under the bridge on the beach.
1)The allies are worthless and only reduce your coin gains.
2)Shotgun is the only weapon you need. Just buy it and point blank shoot everything in the face. Game won.
For level 21, you quick-hit the button on the right. This drops the greenie down, but watch out to not burn the black.
He'll go for the black, but teleport down below. Hit him with a green laser, launching him up.
When the greenie deactivates the red laser, turn on the lure on the right. Green and black will start moving, pass the switch twice. Stop the black before the red laser (but after the portal) and wait until green ports down again and dies. Then the black will be able to freely drop down to the pink.
 "NGU IDLE"){kind=icon}
 "S.T.A.N.D."){kind=icon}
 "MineQuest"){kind=icon}
 "light-Bot"){kind=icon}
 "Rogue Soul 2"){kind=icon}
 "Superfighters"){kind=icon}
 "i saw her across the world"){kind=icon}
 "The Last Dinosaurs"){kind=icon}
 "Dangerous adventure"){kind=icon}
 "Forbidden Arms"){kind=icon}
 "i saw her too, with lasers"){kind=icon}
 "Mystery IQ Test"){kind=icon}
 "Linx: Hard Set"){kind=icon}
 "Monster Arena"){kind=icon}
air combos replenish more bp compared to bloodsprays. also, upgrade 'scarlet synthesis' and most of bloodlust aura.