I agree. What I'd really like is for these people to sit down and come up with some more levels though. It's got 45 levels and I think 14 or 15 "secret" levels. Once you complete the 45 main levels, it unlocks 45 mirrored levels which are the same levels, just mirrored; not all that imaginative.
Also, to complete any level you need to collect all the red crystals, however; the crystals don't need to be collected in one life and there's no benefit for doing so. And since there's no life limit, you can throw yourself at the crystals and die after collecting each one and still clear the level fine. Perhaps the secret levels should have been reserved for those who can complete the levels (red and green crystals) in one life.
The camera is also troublesome at times. It's set at a fixed position from the ball. So when you're rolling forward, it works fine. When your rolling backwards (towards you), things can surprise you since you had no indication what was coming. I very often find that I have to pause the level and view the map to figure out where to go next. I will say that the map view is infinitely better in Marble than in Monkey Ball.
Basically the game is a bit on the easy and short side but definitely a good one that I'd highly suggest renting if not buying.