The audio file’s length is to be matched, & often, the tone & intent of the original actor as well. Casting generally mirrors the established tone of the Japanese version (for Japanese games I mean), although there are a few games that take liberties (MGS, off TOMH, being one) where they sound very different.

Dub budgets, while JP games are a much bigger industry than anime, are still similar-ish for the smaller games, & generally use very similar talent, mostly the same people. Some of the bigger games, like Final Fantasy, MGS, & a few others, are so big that their dubs have more cross-over with original English works. However even Kingdom Hearts’ English dub (what with its Christopher Lees & Mark Hamills) still has a “typical” anime/J-game dub director.

Don’t get me wrong, I think dubs are cool & often let me listen to the tone & characterization without language barriers. But I’m not sure why exactly we’d differentiate anime & game dubs, when the business reasons & process of them are virtually the same.