if some lines are too long, it will be forced to be newlined.
for example, normally a long line will looks like this
1 first line
2 this is the long
This answer is derived from @mario-rossi 's answer (Kudo to him), with minor midification.
I use the normal UP and DOWN arrow key, rather than CTRL+up and CTRL+down. And somehow I need to remove one excess space in the INSERT mode mapping to avoid an off-by-one behavior.
Put the following into your ~/.vimrc:
" When a long line is wrapped, the "gk" and "gj" allow you to move up and down
" a visual line, while normal "k" and "j" move a physical line.
" The following settings map "gk" and "gj" to cursor and .
map gk
map gj
" And the following lines enables same and behavior in INSERT mode
imap i
imap i