A survival action game where a player must survive "day" and "night," which are switched every 10 second.

During the safe "day," a player should destroy monster's eggs and during the dangerous "night," he/she should run away from looming monsters.
To win the game, the player should activate the sonar to observe enemies and attack monsters' eggs at the moment when the day is changed into the night or vice versa.
If he/she misses the timing of starting the sonar, monsters will attack him/her in a moment.
No time (seconds) left before the moment of change is displayed. The player must depend on his/her own countdown. The work is thrilling and the tempo is good.