Resident Evil

When starting a new game, you are asked a question: "How do you like your games?" Choosing the first option "Like climbing a mountain. Fulfilling, but takes a lot of work." is actually the "Normal" game-mode. The other two questions ("Like going on a hike." and "Like taking a walk." represent easy and very easy, respectively). Upon completion of the game once, the title screen will change to reveal a Green Eye and in place of "New Game" is "Once Again." All difficulty modes will have their proper names at this point.

Normal difficulty adds more zombies to the mix, a few more Cerberus and Hunters and all the enemies take more damage to kill. Chris or Jill can take less damage now, on Normal one bite from a zombie will send you into "Yellow Caution." Health is represented by the heart-rate machine in the inventory screen. Green or "Fine" is max health, "Caution" with a yellow tint is around 70%, "Caution" with an orange tint is less than 50% and "Danger" is less than 30%. As you take more damage, your character will begin to limp though unlike older RE's they will not drag their feet. Around Orange Caution is when they will start holding their side. Remember, about 3-4 bites from a zombie is all that's recommended before you definitely need to heal. Always check your health after an attack, some won't do much damage (like certain Hunter swipes and Cerberus bites) while others might put you straight down to danger.

Health items, defensive items and ammunition are also more scarce. Unlike later Resident Evil titles, enemies will not drop health or ammunition upon death. It's all found around the Mansion and surrounding locations. In normal mode, there's just enough to likely kill most enemies in the game though it's recommended to save your ammo and use it sparingly. The more shotgun ammo you have by the end of the game the better, by example. 

Combat, if you choose to engage (almost all situations outside of a few boss fights can be evaded), should be utilizing weak points on the enemies. For zombies, this is their heads and legs. With the shotgun, aiming up and firing at the right time could blow off their head in one shot. Other times it might not, and this usually occurs when you already dispatched an enemy with a decap earlier in the same area. If you kill a zombie and a pool of blood forms around them, they can return as a Crimson Head later (the only zombies incapable of this are found in the Umbrella Labs, the naked ones). Crimson Heads are faster, more dangerous foes and should only be confronted with high-power weapons. 

A few more notes: Saving is done with Ink Ribbons, mostly located around typewriters (which are used to save, like in Resident Evil 4 and Resident Evil CODE: Veronica X), items can be stored in item boxes (which link to all other item boxes, unless in Real Survival mode) and most give off a "flash" so you can spot them on screen. 

Now, methods for completing this. Avoid as many enemies as possible, learn how to run passed them (see "Don't Stop Running" for more details) and learn the layout of the mansion. Save often, clear out rooms only if you absolutely need to and gather as much ammunition/health items as you can muster. A first run-through should take around 6-8 hours, maybe less. 

The achievement will pop on the Results Screen at the end, along with preceding achievements "Like Taking Candy from a Baby" and "Not In the Mood to Die" (very easy and easy difficulty modes).