According to Clover Studio's president and God Hand's producer Atsushi Inaba, the game was originally going to focus on "hardcore action" with little to no humor. However, after showing a trailer for the game at the 2006 Electronic Entertainment Expo (E3) which contained some comic relief, the team decided to integrate a large amount of comedy into the game based on the viewers' reactions. Mr. Inaba stated:

"So the original concept was a very hardcore action game -- a game that you had likely seen before but a game you wanted to play because it was a fresh take. When it came time to show the game at E3 we decided to make a trailer that had some comedy aspects in it because we thought it would be fun. Then we saw everyone's reaction to the trailer and thought, 'you know, what if we put some more comedy into this game?' So, the comedy grew out of that and became a much bigger portion of the game."
Contributed by ZpaceJ0ck0
According to the game's director Shinji Mikami, when he played Final Fight: Streetwise he hated the game's direction and believed it to be a terrible entry in the series. Mikami thought about making a similar game, which would later become God Hand.
Contributed by ProtoSnake
In Stage 5-1 of God Hand, Gene encounters a drowning man being teased by three enemies throwing Life Preservers at him. If the player defeats these enemies there will be a cutscene where Gene will save the drowning man.

However, if the player decides not to save him or engage the enemies, the drowning man will say "I won't be back" and put his thumb up as he sinks parodying Terminator 2's ending as well as the catchphrase "I'll be back" which the films created.
Contributed by retrolinkx