I think it may come down to acceleration. If you press boost, you suddenly start going very fast, and it means you have to react very quickly to stuff. The turning circle without the anchors is very wide which makes it almost impossible for a new player to successfully manoeuvre in caves without anchors. I think either lowering the acceleration, allowing the ship to take a hit or two before exploding, or moving the caves levels later would eliminate the frustration. I must stress I didn't find the game frustrating once I got to the wide open levels.