The test isn't too bad, the sections are timed, but as long as you are good at grammar/spelling, some math and problem solving you should be fine. It's really used just to weed out the idiots, because trust me, every customer that comes in there always thinks they'll make the greatest employee (and 80% of your customers will probably be on welfare to begin with), and it's just an easy way to let them down and keep their business instead of outright rejecting them.
Just some advice for you - take the part time position if you get it. You'll be working a 4 or 5 - midnight shift most likely since managers tend to work during the days. The company is open every day of the year including Christmas, and guess who gets stuck on those holiday shifts

The benefits are that you'll get free rentals obviously, and all movies and most triple A title games a week in advance of their street date to take home and play with. You'll also earn $1 commission per DMRC (discount movie rental card), which doesn't sound like much, but if you are a good salesmen and in a decently busy store, you should have no trouble selling at least 100 cards a month even at 25 or so hours a week. That's $100, easy money.
I will warn you now, do not go into management. I won't get into the shadiness unless you want me to, but you'll have fun at the part-time or even full time level (although the company hates full-timers except for management staff. They're stingy about money and don't wanna give you insurance unless they think you're worth it, i.e. management).