Penumbra: The Remake

[DjSimplicity]

THAT, is something i have dreamed of for a while now!
So, basically, i have to update the engine and so forth.. What do i need to know to update it?
Like coding and so forth, and HOW do i update/rewrite the engine?
And lastly, who do i talk to about getting the right's to making a remake, if possible?
If there is no chance in hell i can make a remake cause of © or no permission, i would
still like to know how to improve on the engine (since it's free for use?).

Thanks to all who can help me along the way!