how can i update the whole system ?

Can someone tell me what do i have to do to update the whole system including all the apps like Chromium, Kernel and all the rest ?
A emerge -u world just updated KDE to 4.5.5 but not the rest

Read this manual.

a application like “entropy” in Sabayon would be nice to have in Calculate too

Are there any plans to implement entropy into calculate Linux too ?

Entropy is the front end of the portage. In recent years, Emerge has improved working with the binary package. I hope we do not need to invent yet another front-end. In any case, need to gain experience working with binary packages and maintenance of rolling-release.