The in game timer does not work for a ng+ run of dead space 3. the approximate real time is 2:56:47.

Dead space 3 NG+ casual

First off, the weapons
The weapon used throughout most of the run is the Devil Horns, they are an unlockable weapon that pretty much one shots every enemy bar the very late game alien necromorphs.
The second weapon used is a detonator mine with a force gun secondary, this weapon is used for a particular section on the terra nova, and the suit repair skip.
The third weapon used is a timed mine needed for the nexus skip.

Most of the areas are natural route, except for the 4 skips in the game and a few tricks.

The first skip is early on in the run and invoves flying through a non-solid wall on the roanoke and checkpoint restarting to save about 30 seconds.

The remaining skips take advantage of boosting, in Dead space 3, running (usually running backwards) into certain walls will allow you to climb the wall, the rate and ability to climb the wall depends on the framerate, hence why most of the skips used in the run do not work on console.

The second skip used in the run is the Suit repair skip, it is about an hour and 5 minutes into the run and is the first major reset point. It involves using the aformentioned boost to break out of the map, then navigate an area of solid mountains that is invisible.
There are holes in the terrain everywhere and the lack of vision makes it very hard to navigate. I use detanator mines here to gain a visual reference and assure that i do not get stuck on terrain, which can be an issue.
This glitch can be done in 2 ways, a method with, and without dying. I used the dying method in this run because i find it easier and more forgiving, because of the heat-death timer. When i fall at the end of the glitch, i fall through the next checkpoint, hence why i reload with a repaired(ish, the suit is still broken) suit.

The third skip used in the run is the Nexus skip, a little past the suit repair skip, it is the second major reset point in the run.
The skip involves breaking out of the map in the nexus chamber, climbing up to the top of the map and crouch clipping to get onto a higher platform.
Once out of the map, the timed mine is used to launch the player a specific direction and distance to pass through the checkpoint after the nexus area on the other side of a locked door. The player than falls to their death and if the checkpoint was hit, they will respawn on the other side of the door.

The final skip used in the run is the Alien Machine skip, this is right at the end of the game and is fairly easy compared to the previous 2 skips.
It involves boosting out of the map and onto the wall that joins to the door that opens at the end of the chapter. after going across and boosting over the obstacles on the wall, the player then drops off at a specific spot to hit the checkpoint past the door.

Apart from these major skips, there are 2 other trickes used to save a little time, these tricks are strategic checkpoint restarts which save time, and the other is crouch clipping through doors that open upwards.

Overall, most of the run was pretty well done, had some issues with wierd and bad enemy ai, and the rosetta labs was pretty poor. There is defenitly alot of room for improvement, though with single segment, with 2 skips back to back both with very high failure rates, getting full runs is very difficult.
The in game timer for dead space 3 is glitched in ng+ runs, and therefore cant be used.