BubbleBobble is one of my favorite games for the NES/arcade. In it, you play as either Bub or Bob - a human boy transformed into a bubble-breathing dinosaur and cast into the cave of monsters to rescue your girlfriend from the evil Baron Von Bubbla. It's ridiculous. It's full of really cool secrets (including a set of 10 hidden levels and some random items you may never see pop up in the game's 100 levels). It has a catchy song that is already stuck in my brain just for mentioning it.
I like doing these game stickers because my familiarity with the subject matter allows me to sketch them out with little-to-no research. My only goal is to capture the spirit of the game, and to make it recognizable. In this way, I am able to figure out and put forth my own personal style.