you decide a game name on several factors;
content / characters / story
Final Fantasy - It is the 'ultimate'/'last' fantasy adventure as it deals with the theory of Ghia the planets soul that controls life/death (hence why it is the last Fantasy).
Jakk & Daxster - Cause those are the main characters
Unreal Tournament - The first game was named after the engine as the graphics were described as awesomely 'unreal', Tournament was added because it was an online game aimed for tournament play.
Tomb Raider - Cause Lara runs around in Tombs all day (or atleast did in the original)
Grandia - the first game was the first long game ever; 80hrs of gameplay (for 1994 that was amazing) so it was a Grand adventure
Play with forumla a bit and i'm sure you'll come up with a good name; and remember until you release your first real candidate you can always change it.
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