Summary:

The NEET Yamano Masaru (23 y/o) went to Hello Work and finds an interesting job offer. [A swords and sorcery fantasy, test play for Miniature Garden of Razgrad World. Extended period of time, preferred to be able to live on site. Monthly salary of 250,000 + percentage pay.] Immediately goes to the interview and signs a contract. However, the place of employment is another world. Because of the contract he's taken there, to survive Masaru received a cheat, but he is told the shocking truth. "This world will be destroyed in 20 years." Can a simple NEET prevent the destruction of the world?!

Resources:

http://myanimelist.net/manga/113558
http://www.mangaupdates.com/series.html?id=147953
http://www.novelupdates.com/series/im-a-neet-but-when-i-went-to-hello-work-i-got-taken-to-another-world/