At the end of the day though, the biggest restriction we had to contend with was home made. Even before we wrote one line of code we had laid in stone that the game MUST run at 30 frames per second. For the type of action we were aiming for I honestly thought that I was setting my guys up for a near impossible test. Sure enough, many times through the dev cycle, we dropped to 20 or 15fps. At these times you would hear the odd murmur of 'we can't throw that much around screen,' or 'we need fewer attackers on this mission' - we never once backed down or compromised though.
What we did do many, many times is go over the code, hand optimising every line we could. The amount of raw machine code in this game is just unheard of nowadays. We were busy throwing away page after page of traditional code in favour of the machine's raw assembly language. Sure, this massively added to the development schedule of this project, but at the same time it created a game that I feel could not have been created anywhere else on the planet. Sam (Houser, President of Rockstar Games) had given me the remit of creating a DS game that would rival Nintendo's own best offerings, and he wasn't about to let any ticking clocks get in the way of our success.