Harry Potter and the Deathly Hallows - Part 1
49 Achievements
1,000
15-20h
Defeated 1000 Enemies
Defeat 1000 enemies in Story Mode.
75
How to unlock the Defeated 1000 Enemies achievement in Harry Potter and the Deathly Hallows - Part 1 - Definitive Guide
Through the story mode, just kill every enemy you come across. This particular trophy should be earned very close to the end of the game. I earned mine about ten minutes before the game came to a close. If you miss this trophy during one playthrough, it does carry through to additional playthroughs. Just keep defeating enemies and you will recieve all other defeat trophies as well as this one.
For these achievements, simply destroy or defeat the required number of enemies. This can also include Dementors. The level in which you follow a Patronum through the woods has a huge amount of spiders in it. I suggest standing still when you get to each batch of them and letting them spawn until there are none left. Then move to the next batch, repeat. These achievements are cumulative, and if you don't have it by the end of the game, you should get it within the second level of another play through.