Wikileaks, though technically not a wiki, provides an easy means to disseminate information that some find it desirable to share against the wishes of those who find it desirable to keep secret. Aside from the morality of the leaking itself, such a service provides a look into the activities of...
Work out how the gravity affects your jumps in the early stages so you know what to expect later on.
Check the map often in the Adventure mode to see where you've been.
Sometimes it's worth a sacrifice to get to the checkpoint.