Making a game?

So…I’ll be honest. I haven’t done a whole lot of work towards my final project outside of the brainstorming phase. I’ve decided I want to try my hand at creating a game, perhaps something involving a science-fiction setting. I want to drive the player to make a choice they don’t want to make, almost a lesser of two evils scenario. I have the concept pretty much down, but the practical side is coming up short. I have essentially no experience with creating games and my one experiment ended rather poorly…so if anyone has experience with choosing a good program/method for game creation, I’d sure appreciate your expertise in this matter.
I’m also searching for some clarity about the format of our presentations. I know its 20 by 20, but is there supposed to be some overarching flow here? Or do we have creative license?

Thanks — Will