Bokurano (2007)

During a seemingly ordinary summer vacation, a band of 15 children stumbles upon a secretive man dwelling in a coastal cavern, surrounded by an array of advanced technology. This enigmatic individual introduces himself as a game developer, crafting a unique video game that pits 15 colossal robots against alien invaders threatening Earth. Intrigued and excited, the children eagerly agree to become his beta testers. However, their initial enthusiasm swiftly morphs into dread as the boundary between the virtual and the real blurs. The game's hyper-realism becomes increasingly terrifying, especially after the grim reality of a comrade's demise follows their first triumphant victory. As the stakes rise and the line between the game and reality becomes indiscernible, the children are thrust into an unforeseen predicament. They must confront the chilling realization that they are ensnared in this deadly "game," with no apparent way to escape or halt its relentless progression. Their summer of adventure quickly spirals into a harrowing battle for survival, where their childhood innocence stands on the precipice of an unforgiving reality.

Bokurano is an anime show featuring Hiroyuki Kinoshita and created by Kimitoshi Chioka.

Bokurano is currently streaming on Crunchyroll, Crunchyroll Amazon Channel and Funimation Now.