You can easily beat the game on hard mode by using the INVINCIBILITY GLITCH as showN in this video.
All you need to do is build up your slo-mo bar in the top left corner, then as soon as you get it to 100% you activate it then restart the checkpoint then you are invincible to enemies bullets.
IMPORTANT::Glitch Must be set back up, at the start of a new level. Also glitch does not work against Helicopters, Rockets, or when in a driving sequence!!!::
ADDITIONALLY: You can use this glitch to obtain the "Tomb Raider" Achievement, just activate the glitch and run through the cemetery like Juggernaut LoL.
Thumbs Up Please If This Helped Guys, and before you thumbs down comment so i can help you if you have any problems, thanks :-)
**Credit to NeedtoAchieve for the video**