Three subtly different ways to describe the same thing which isn't a thing at all really. They're the three key words I use when I talk about my love for video games in both making and playing them. First and foremost a Game developer must be dedicated, in more than one way but above all else they must be dedicated to themselves. As narcissistic as that may sound it is the truth, one of the greatest downfalls of developers is the urge to just give up and let it all go. If you don't dedicate yourself to accomplishing the task and then rededicate yourself to your own cause you'll simply drown in self doubt. You must also be passionate as if you don't love what you do and believe in then you can't possibly dedicate yourself fully to it there will always be something else you're holding on to that will keep you from being your best. Then there's obsession. You must have some kind of obsession to make a game, a deep longing that can't be filled an almost romantic desire for something unattainable. Conversely it may also be a deep seeded loathing though I advise against that route unless your game is intended to be potently violent on degrees that would put manhunt to shame.
I recently wrote on the topic of recognizing passion, what it is and how to know it when you see it. Though the second half of that is still in draft. I'll briefly discuss dedication and obsession. Dedication is a willful state in which you're compelling yourself to something be it love, revenge, a task, or any number of other things. Unlike obsession it takes focus to dedicate yourself and is more of a tool to be used than an entity that can consume you. The downside of dedication is sometimes it's hefty price as not all are prepared to handle all the strings than can come with it. The mental fortitude necessary to sustain yourself in your pursuit can often cut you off from things without even noticing which in part is it's power though also making it a double edged sword.
On the topic of obsession however it's quite the opposite. It's a part of your body and mind to the point it guides you without even considering it directly. If you don't keep it in check it can easily consume you completely and beyond that point your dedication is to your obsession and essentially wish fulfillment of whatever your obsession is. Though often even if you succeed your obsession doesn't just go away it will always crave more. Truly it is a beast. Though that's not to say it's without use, regardless of how dangerous it can be, it can easily be trained to do your bidding and all that you need beyond that is a leash to reel it in when you need to. It can make for an excellent guide and is exceptional at getting you exactly what you want if you respect it's power.
Balance these three parts of your life and it's only a matter of time before you find a way to make any dream come true in at least some fashion.