Death March kara Hajimaru Isekai Kyousoukyoku is a fantasy manga, released in December 2016 and also has a prequel. Suzuki Ichirou is a 29 year old programmer who is drowning in work and barely gets to rest.
He gets a chance to catch up on some sleep and somehow ends up being transported into a fantasy role-playing game that’s a mashup of the games he was debugging earlier and thinks that he’s dreaming but the experiences seem too real to be a dream.
He soon realizes that in the game, he’s not an adult anymore. He finds himself to be a 15 year old boy named Satou, the alias he used while running tests on games in Death March kara Hajimaru Isekai Kyousoukyoku Manga. While Satou is still trying to figure out his new situation and doesn’t fully understand his abilities, he’s attacked by a high level army of lizard men.
With the help of all three Meteor Shower attack options, a new recent addition he did to the game that helps one wipe out an entire fleet of an enemy army instantly, he defeats the army and his level is boosted to 310 which makes him a high level adventurer.
A high level adventurer has all their stats set to max and this helps Satou gain a plethora of wealth, skills, mental and physical abilities as well as magical powers. With no apparent way to return to his real life, Satou decides to explore this new world, meet new people and live in peace.
Unfortunately, his carefully articulated plan to avoid trouble doesn’t last long and he faces new challenges with new developments in the game.