- Play on Heroic or above. Seriously, anything less is just gimping the experience.
- Contrary to what you might think, Stealth does actually work. It's a bit like Far Cry 2 - the enemies aren't as dumb as a brick and even if they don't know who killed one of their own they will know that it happened and where the shot probably came from. If you stick around they will catch you, but if you stay back and find some cover you can give them the slip and they won't find you that easily.
- The Silenced SMG is kind of meh, but the Automag is very good. The classic "noob combo" works so damn well here: Fire an overcharged plasma pistol blast at a brute and quickly switch to the automag for the headshot. Congratulations, you're virtually unstoppable.
- If you get a sniper rifle, use it. They're limited in ammo but they're incredibly powerful. 90% of the time you will get the jump on the enemy in the overworld and a well placed shot can mess up a brute's day.
- Finding audio logs will unlock supply caches. It's worth doing this as it's the only reliable way to get extra ammo for your SMG and automag.
- Engineers can be a pain in the ass. They sometimes self-destruct if you get too close to them as they've been rigged to blow when they come in contact with a human. They'll also give overshields to any covenant in the area, but a plasma pistol/automag combo will sort that issue out.
- VISR is essential in the overworld but in the flashback missions it's usually not worth it unless you're in a dark area as it amplifies light and can make it harder to see things.