In the end we learned the following lesson, which we should have learned from both Maul Ball and Jailbreak - no matter how fun the initial versions of the game are you need a design doc or else the gods of gaming will shit down your neck.
So we made a checklist of things that absolutely must be done before work starts on the next game - things we have till now either just avoided, talked around, or hoped it would all sort itself out through "tweaking". Do your tweaking in the design doc.
I'm not going to give too much away yet, because we still have to work our way through the design phase and have to check feasibility and get the idea critiqued and such, but at the moment we are thinking of making Kernel Chaos. Kernel Chaos was one of my very first formal designs, which I wrote a almost 2 years ago. At that stage the game was far beyond my reach. If we do decide to go ahead with this game I am going to use every 3rd party library / tool I possibly can to get the game running as quickly as possible, and also to allow Kev to work on the art / music knowing what formats will be support from the very beginning.
But thats all in the future, right now we have to concentrate on putting together the best possible design doc we can.