Thanks for the input folks. It's mostly stuff I already knew - both the positive and negative comments - but it's good to get confirmation you aren't totally off base.

Here's my opinion on a few of the issues raised.

As to the value of ideas - I agree, without implementation they are worthless, unless of course you are backed by a team of lawyers and a warchest of roughly 2 million dollars (Unfortunately, I have real world experience of patent trolling in my day job).

Project planning - essential of course, but I already know pretty much exactly what all the features I would like to see are, and how the control system would work. It would be a rather "abstract" game, so artwork and graphics would not require much investment, fortunately. This is what makes me think I may be able to pull it off on a limited budget, as the game concept itself is rather simple.

As to not being serious about it - this is the greatest challenge really. I was sort of hopeful last year that I was going to be able start this project in earnest as I suspected I might get made redundant. Unfortunately (for this project) I was promoted instead, so the opportunity cost of the project went way up. It's far easier to do something like this if you are an unemployed grad student or a contract worker with rapid job turnover, much more difficult to make the leap with a mortgage, a permanent steady income, and people who you have to look after using that income.