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...
Use your double jump to adjust your trajectory during a jump.
Explore alternative routes to bag all of the coins and track down that elusive star.
Checkpoints will allow you to restart midway through the level, so be sure to seek them out.