Anomalies:

Senzu Beans:
Notice how they have senzu beans when ever they need then but senzu beans take long to harvest (They said in one of the episodes) and when ever the get some beans that take all that were is.

USSJ Trunks:
Notice that Cell tells trunks that trunks power is far greater then his own. But when cell fights Gohan his power is not far weaker. A USSJ is far weaker then a SSJ2 so this means that Cells power is incorrectly changed throughout the story.