Haha alright, let me try to sum it up in a more accessible way: You play a video game and as you are anticipating a reward (e.g. level up) your brain will release dopamine, to motivate you to work for that reward. This dopamine will be released from the ending of one nerve, traverse the space between two nerve endings ("synaptic cleft") and then activate receptors on the end of the other nerve. This will initiate a signaling cascade at the end of which FosB levels, in the recipient nerve, will increase.
Dopamine will quickly leave the synaptic cleft, the signaling cascade will cease to be active and FosB levels will just as rapidly decline.
Now problems start to arise if (or shall I say when) the frequency and intensity of the dopamine bursts exceeds physiological (= normal) levels. In that case, FosB will reach high concentrations, which will cause certain enzymes to truncate FosB into Delta FosB. Without going into too much detail, delta FosB - as opposed to FosB - is very stable. When FosB levels decline after seconds to minutes, delta FosB can remain elevated for weeks to months.
What delta FosB does I can't tell, at least not exactly, because even for someone who went through med school this kind of information is more than I deem relevant to the cause. But delta FosB will lead to structual changes in the brain ("neuro plasticity"). This could e.g. activate or disable certain genes, regulate transmitter uptake and influence mechanisms that I can't even spell properly. For you this means that FosB can increase your impulsivity or increase cravings. But as a general rule, making the mental leap from "we observed structural changes in the brain" to "we think we can explain certain behaviours" is really a long shot.
But there exists a lot of evidence that supports the theory that delta FosB is the switch that keeps you addicted. It'll keep craving for games (and stimuli), it might make everything seem boring and whatnot. It's not the sole cause, obviously, but it plays an important role.
At the end of the day, what this means to you, is this: