Game features:
1. Easy to use, leisure and entertainment.
2. Test reaction and observation ability.
How to play the game:
1. Click the screen to start the game.
2. At the beginning of the game, the monster appears at the top of the screen.
3. Click the screen to start, shoot monsters and prevent monsters from crossing the defense line.
4. Each game has 3 chances, and 3 monsters cross the defense line to finish the game.