Hi mission and welcome to GameBoomers!

I think what they mean by Slideshow Presentation is that you can't pan around the environments, the way you can in most 3D games or in node-based games with 360 degree panning. Instead, you click (or double-click) to have your character exit the screen, and then you are presented with the next screen or location.
Yes, the game will probably play in a way that is similar to Nibiru, and from what I can tell, the graphics will be somewhat similar also.
Have you played Martin Mystere? The same company that developed Martin Mystere also developed Belief & Betrayal.