Well your not going to learn how to make a game in 10-20 hours..... Sorry but it's just not going to happen!
Your best (if your not interested in investing the time to learn programming) to try and find a free game engine, and source code, and then implement your own content, and maybe small snippets of code into that. (as you learn)
anyway, good luck!
www.stevenegan-cgi.com
"Your weapons are no match for ours! People of Mars, surrender!"
"Um, this isn't Mars. This is Earth."
"Earth? Earth-with-nuclear-weapons Earth?"
"Yes."
[long pause] "Friend!!"