There appear to be 5 levels. They can be summed up like this:
LVL1 (Dune): Complete
LVL2 (Cave): Complete, Only 1 Enemy
LVL3 (Dune2): Remake of LVL1, new volcanic terrain color matches the level theme
LVL4 (Treetops): Empty - just some enemies walking around LVL5 (Mountainside): Empty - Just some enemies walking around

95 dollars pour ça .