Ever video game should be simple and I should be able to easily comprehend everything in the game immediately
Highly prejudiced and biased opinion incoming:No.
No they should not.
You should be able to comprehend some things, but certain things you should be kept in the dark about. It's what makes a game good, in my honest opinion. Not knowing certain things and not being able to instantaneously dicern the plot makes me want to keep going. It makes me wish to find out what happens next. Like a book, or a TV show.
If they just handed you the plot on a shiny platter, ready for you to consume in a matter of minutes, I would go, "Nope. No. Nuh-uh. You are going right back into the store." I like games that tell a story and have a degree of complexity to them. If it was all oh-so-very simple, then I would not feel that sense of accomplishment I get from solving a puzzle, or beating a massive boss, or even the game itself.