You are stuck on planet cheese. You could slice your way out if only you had a slicer. Luckily you have a slicer detector...
Use the slicer detector (X) to pinpoint the location of the slicer. Thrust with either up or O (whichever you use first) and fire the horizontal course correction engines with the left and right buttons.
You need to refuel every now and then. The cheese of Planet Cheese can be processed and turned into rocket fuel. Land safely on both foot pads at a low velocity to process cheese.
UPDATE (V2):

Camera locked on player; no easing. This makes precise navigation easier. This also makes the camera lock mode useless, so it has been removed.
Collision detection has been improved, and the vertical velocity threshold for safe landing has been increased to 1.5 pixels per frame. The safe landing threshold is now also consistent and you can't randomly land safely at greater velocities.
For a safe landing, both foot pads no longer need to be completely on the ground. As long as they both touch, it's fine, making landing easier on smaller surfaces.
The player can now thrust with either up or O, depending on which is used first, making it more joypaddigital stick friendly.