This game does not feature a Survivor difficulty. When you select 'New Game' from the menu; you're presented with the standard three options, you need to select Hard.
There's no end game exploit, but there is an invulnerability glitch you can utilize once you reach the game's fourth area, Siren Alley. It involves the Scout Plasmid. Personally, I was able to reach this point without dying on hard, even though I never strayed too far from the objective arrow (this was my second playthrough). So if you're moderately good at shooting games (or have good tactical awareness) you should be able to pull off a one-run completion.
For those interested in performing this exploit:*** Spoiler - click to reveal ***Once you reach Siren Alley, head to the Gatherer's Garden and purchase the Scout Plasmid, before high-tailing it back to the nearest Gene Bank. With Scout selected, activate the Plasmid with followed by a press of the to access the Gene Bank. From there, swap out the Scout Plasmid with any other available option and return to the game.
If done correctly, your character will still be in Scout mode; press to exit this view and from that point on, you will be impervious to damage. This exploit will stop if you gain Adam from a Little Sister, purchase any new Plasmids, or complete a level. If you do lose your invulnerability, it's just a matter of locating the nearest Gene Bank to perform the swap again. This lets you bypass enemies and walk straight to the objective (or find collectibles, if it's your first run).
With the number of missable achievements and collectibles, I still recommend doing a two-playthrough run. The first on easy to ensure you don't miss one of the fourteen missable achievements (which includes a no Vita-Chamber run) followed by a quick run on Hard mode (at which point Vita Chambers may be renabled). It took me ~3 hours or so to complete my second playthrough using the above exploit, so it was worth it for me.
I considered writing a solution to help others, but exploits such as this often polarize the userbase; those who are fine with using glitches so long as it completes the game faster, while others swear against doing so. I'm not fond of the voting war that results, so I'll keep my comments here for vigilant players like yourself to find!
Player Engagement and Features staff at DestinyTracker & HaloTracker. Come stop by!