How and why did Rome fall to the Germanic tribes?

From Internet:

1. Invasions by Barbarian tribes
2. Economic troubles and overreliance on slave labor
3. The rise of the Eastern Empire
4. Overexpansion and military overspending
5. Government corruption and political instability
6. The arrival of the Huns and the migration of the Barbarian tribes
7. Christianity and the loss of traditional values
8. Weakening of the Roman legions