my first impression
of DuckDuck 

Okay, what's this deckdeck?
Can I change fonts? That would be awesome.

No, I can't.

Okay, what's this deckdeck?
Can I change the layout of the default slides?

No, I can't.

Okay, what's this deckdeck?
Can I change the color of slides?

Oh, yes.

Okay, what's this deckdeck?Can I add background images?

Sure.

Okay, what's this deckdeck?
Does is support ⌘Z for undo? Does it even have »undo«?

No, It hasn't.

Am I satisfied with what deckdeck has to offer?

Of course not.

Is it my own fault? 

Hell, yes.  

It's open source, isn't it?

I didn't check any deckdeck repo, yet. But if it is as open as it pretends I should be able to commit my own ideas and requirements and make them work. 
That's how it's done. 

→ GitHub