I know what u are referring to.  

If u watch the promo video it shows you get "millions" and millions of points the more you get the ball to go up the ramp to the rotating island when it is counting down from 30 or 60 seconds. Thats what stands out to me to be the "huge" scores compared to others.
 I dont play this game with points in mind, but rather to complete the "full mission" of delivering the "lava seltzer" to Kona. (this is the aim of the whole game and a really cool and fun mission which the video shows).

It is like Teenage Mutant Ninja Turtles in that you can "complete" the game by achieving a certain "end point" in the game. In TMNT it is called "turbo ginsu" which happens on a 2 player game (or a single player game with updated roms). Effectively, by getting to and past this point, u have "clocked" or finished the game by what u can achive play wise, although can can keep playing n scoring, but its the end of the "story game" so to speak. Gilligans is the same, by giving the "lava seltzer" to Kona, you have completed the "full mission" etc. Fun games. Really fun games.