The entirety of "Halo 5's" campaign mode will reportedly take about 15 hours to be completed.

If the 15 hour estimate proves accurate, then that would mean that the campaign mode for "Halo 5" will take twice as long to finish as the campaign mode in "Halo 4."

According to We Got This Covered, the 15 hour estimate may actually be on the low end of what developer 343 Industries initially had planned for "Halo 5." The game's developers reportedly had designs on making the campaign mode for "Halo 5" thrice or even four times as big as the one found in "Halo 4," but ultimately, they decided against doing so.

Although a 15-hour story mode may not seem to be lengthy at all for role-playing games (RPG) players, the mark is still quite significant, especially for a first-person shooter.

As of now, there's no way to find out just how accurate the 15 hours estimate for "Halo 5's" campaign mode actually is, but players will get the opportunity to find that out soon enough.

In related news, it looks as though the theme music and some Warzone menu images have also been leaked for "Halo 5."

The theme music was leaked through the "Halo 5" beta that was released back in December. According to Gamespot, an update to the unplayable beta led to the theme music being revealed and subsequently being leaked.

The soundtrack for "Halo 5" was made by veteran composer Kazuma Jinnouchi.

Some images of "Halo 5's" Warzone menu were also leaked recently, although there's not much new information to be gained from them other than to actually see what they will look like when the game is released.

For their part, Microsoft has said that the theme music and images are indeed part of "Halo 5," although they did describe the incident regarding the leaks as "unfortunate."

"Halo 5" will be released on Oct. 27.