"What type of game you are developing - 2D / 3D? "
2d-Platforms game

"When it's slow: loading, rendering, sound, AI, etc? "
Rendering alpha effects, for example. People say that DXSpriteEngine isn't very good when loading lots of sprites (anyway, I find this component to be very easy and powerful when you have to scroll a whole world, for example. This task can't be done with Omega)

"Minimum Windows version requirement? "
Window 95, but I don't really mind about this.

"Minimum hardware specs? "
I'd like that my game could be played in a not so high-level computer, but I don't know If I'll manage to do this. I use speed based on time, and the game runs fine between 25 and 70+ FPS.

"Maybe some other hits?"
I'm using DelphiX and I want to choose either Omega or PowerDraw, and I'd like to take an option that doesn't require days and days of "trying to understand" how all the stuff works.

What I really need for now is an efficient way to manage backgrounds (made up by 32x32 tiles), scroll the whole world (all the layers and sprites) and collision detection between sprites.