To make the game more challenging, there are levels you have to reach before you can buy more powerful ships, shields and guns. It's actually a lot more fun this way. You should love the game, since it has a good mystery story line, good graphics, an unbelievably huge (for a game) universe and lots of secret goodies (wrecks where you can recover guns and cargo, jump holes that take you into new systems, hidden bases to trade or fly missions from, asteroid fields you can mine). And once the story line is over, the game can go on as long as you want it to!
Don't rush through it. Take your time and get the most out of it. Juni, whom you'll meet right away, will ask you to rush off to fly missions for her. But you don't have to hurry. She'll wait whilst you explore and just generally have fun.
Great game!