Quote: "i am not using win zone. i am using objective to kill 3 enemies and the level completes, but how to add a video when the player win."
...here's a suggestion:
1. Set two of the three enemies as Objectives.
2. Set a Dynamic Immobile Entity as an Objective.
3. Set the (non objective) third enemy to spawn a Triggerzone, when killed.
4. Set the Triggerzone to play the video you wish displayed, and to kill the Dynamic Immobile Entity.
Just theory, but this should provide close to the illusion that you're after...all of the enemies are killed, a video plays, and the level ends...