It sounds like you were taking quite a bit this week! My suggestion is for Game-A-Week is to start simple and go up from there. Because of the strict deadlines, it will force you to handle other aspects of game dev like polish and deployment which is generally neglected for games with longer dev cycles.
Once you have a pipeline in place for deploying builds, it becomes a lot easier to focus on execution for ideas since the boring technical stuff has been resolved.
I hope you stick with Game-A-Week! There's always a lot to learn and it sounds like you got quality experience on this attempt.
Thanks for your comments. I'll probably not entirely follow the Game-A-Week methodology because I'm a wannabe indie gamedev and I'd like to work soon on a commercial project ! But I think this is a fantastic thing to do for anyone who wants to become serious about game development. One similar alternative is to participate frequently to game jams.