Death March to the Parallel World Rhapsody

Death March kara Hajimaru Isekai Kyusoukyoku (in English, Death March to the Parallel World Rhapsody) is an ongoing novel series (2013-present) by Hiro Ainano. As of January 10, 2023, 27 light novels had been published in Japan, with 17 of those translated into English.

Ichiro Suzuki is a 29-year old gaming programmer who was tasked with fixing several bugs in two MMORPGs his company is preparing for publication. However, he becomes extremely worn out as he is working during the weekend. After taking a nap, he mysteriously wakes up in another fantasy RPG world as a 15-year old named Satou Pendragon, a nickname he uses while running beta tests, and with what looks like the menu screen of the game he was working on appearing before his inner eye.

However, before he could grasp his current situation, an army of lizardmen ambush him and launches an all-out attack on him. In desperation, he uses all three of his special "Meteor Rain" attack options at once and wipes them all out. As a result, his level jumps from 1 to 310, maximizing his stats immensely. With no way to return to reality, and as a high-leveled adventurer armed with a myriad of different physical, cognitive and magical abilities and weapons, he sets out to uncover the secrets of this new world, earning the trust and affection of many people in the process.

Death March kara Hajimaru Isekai Kyusoukyoku is available as both a web novel series and a light novel series. There is also a manga version (starting December 2014) and an anime adaptation (broadcast January 11, 2018 to March 29, 2018, with a translation available on Crunchyroll).