How do i work with performance?????

Hi, i’m working in an interactive walkthrough in a house. I started with the kitchen. For my client the kintchen it’s still empty: i have some modulars, a table, a cup, some boxes, a smoke generator and 3 textures in total.
But today i found that when i add just one another object (a frying pan that i made with spin it’s few polys) i can’t move in my scene, it’s overloaded.
I’m using these for walking the scene
it works but i need to add a lot of objects to my kintchen (it’s empty for my client !!!)
The quality of my wakthrough needs to be like this:

so the question is: can i do this job with the game engine??
I’m just begining and i really don’t know what can be done or how to deal with this performance problem, i think that my kitchen it’s quite ok by now, but it’s fundamental for me to add more objects.

I think that the engine will handle ok the number of objects in the picture you showed. Keep the polycount as low as possible, thou.
Just to test the performance on your system, model, say a chair, and duplicate it several times. Play the game and see the FPS you ge.

The problem is that the scene at the picture it’s just to show the quality i need, but it’s empty, i need to add there a lot of objects and interact with the objects (for example a microwave oven and put a cup inside it, and set the time the cup will be in the oven and the cup stars spining when i start the oven, and things like that). Is that possible?? how do you deal with that? is there any Blender walkthrough (not empty) i could see? i can’t find, i just want to see the kind of things it’s possible to do, or maybe some screens shots i could see, because i don’t know if this job i wanna do can be done with Blender (i hope so)

Should work well, if you don’t exagerate the object count. Join objects you don’t need any interaction to reduce the total object count. And as Arangel already mentioned keep the poly count low.
To a tutorial for that specific topic: I guess there is none. It’s a little bit too specific. You’ve got to figure things out by yourself, I think. But shouldn’t be too hard if you master the game engine basics.
For the counter you can use a timer property for example. The rotation ofthe microwaven oven dish can be done with an Ipo that is played, when a property is set to true. To rotate the dish and the cup you would probably need to end the cup object and add a cup mesh to an emtpy mesh object parentented to the dish. etc., etc., etc.
Just play around. I’m sure you will figure it out.

Total object count isn’t as big as an issue now thanks to frustum culling, but it looks like a lot of objects in just that view along, keep the polys as low as possible and make the detail come out in the textures.