Transported to a game manga name

Question

I'm trying to find the name of a manga in which the protagonist is a game designer who, while editing the game, gets sucked into it, and he has a game window in which he uses Meteor Shower to kill a group of lizard men and attain a high level.

Answer 1

It could be Death March to the Parallel World Rhapsody aka Death March kara Hajimaru Isekai Kyousoukyoku

Synopsis from myAnimeList

29-year-old programmer Suzuki Ichirou finds himself transported into a fantasy RPG. Within the game, he's a 15-year-old named Satou. At first he thinks he's dreaming, but his experiences seem very real. Due to a powerful ability he possesses with limited use, he ends up wiping out an army of lizard men and becomes a high leveled adventurer. Satou decides to hide his level, and plans to live peacefully and meet new people. However, developments in the game's story, such as the return of a demon king, may cause a nuisance to Satou's plans.

Answer 2

Could this be World Customize Creator?

Tagami Yusuke, led by a mysterious voice, is summoned to another world, "Caltsio". He was just a young video-game lover, but Fate decided to make him become the "Evil God of Calamity" of this world, obtaining the ability to create and customize everything, Customize Creation.

Here's part of the translation of the original light novel:

Continuing to move the item, depicted in the 3D game, shown on the screen, with the cursor, he was thinking of how to use the [customization code]. It was a system, used to modify the stats of the item, obtained in an RPG game, however you liked.

While the main theme of the game was orthodox hack and slash (冒険活劇), which is pretty common nowadays, the Item – Customize – Create system played a big part in what got him into playing it.