Okay, time to look through the help file... (p means paragraph)
Bold words are to be added, Stricken words are to be removed.
General: There are a lot of "--" in the document. Often they are used appropriately, but there are instances where punctuation would get the job done, making the paragraphs easier to read through.
Getting Started, p1: Show Player screens are far more than 3 now, more like 10
Getting Started, p2: "Corporal" -> "Private First Class"; space missing just before left parenthesis
Getting Started, p6: perks probably doesn't need quotations; "levelled" -> "leveled"
Getting Started, p7: "Advanced Traits" is proper but "master traits" is not, pick one
Getting Started, screenshot: player's name is supposed to be light blue instead of dark
Getting Started, p10: "sob" should probably be capitalized and/or dotted to emphasize acronym
Getting Started, p11: two instances of -- and one of -, choose one for consistency (applies to any future uses, Find & Replace works wonders for stuff like this)
Getting Started, p12: after quoting each tactic once (since these are words being used in a proper context anyway), future quotes are unnecessary; levelling -> leveling; ...descending to the next level.
Getting Started, p13: no mention of armor #s; ...the number in bracketsparentheses indicates...
Getting Started, p14: need space between Kill and 'em; "rock landscape" appears in other areas, should probably change parenthetical to "such as on the first level"
Getting Started, p16: "u" is also used for pulling levers, may want to mention the priority
Getting Started, p18: needs a mention that the alt-fire button is "F"; "special" from special fire probably does not need to be in quotes
Getting Started, p19: "special" from special reload probably does not need to be in quotes; "Reloading is automatic if you have the proper ammo in your inventory." <-- confusing statement, there is no non-automatic reload, perhaps reword so it is obvious that you will reload as much as the ammo in your inventory will allow
Getting Started, p22: callback to p13, at the very least keep the two paragraphs next to each other (if already fixed in p13, p22 can likely be removed)
Getting Started, p33: "Try to check out the "@" screen...", alternatively, use "character" screen and make note of the button you need to press after
Getting Started, p34: callback to p18, at the very least keep the two paragraphs next to each other (if already fixed in p13, lever mention can be removed; could stand to mention water/acid/lava
Getting Started, p36: "Common - Hmm... thisThese items are..."; "Most of them can beare generated randomly, others are dropped by enemies using them, and still otherswhile some of them will appears in certain places..."; armor/boots can only hold one mod without WK
Getting Started, p37: mentioning unique before they are defined is a bit haphazard; "...usually more powerful versions of standardcommon items,..."; exotics hold the same mods as commons (two for weapons, one for armor/boots)
Getting Started, p38: Uniques -> Unique; (I'm just going to rewrite this while keeping the message clear.) "The rarest and most powerful type of items. Most are fantastic upgrades to their common counterparts, and some carry very interesting properties, including regeneration, penetration, and absolute destruction. Unique items can only be encountered by chance, although certain special levels have a higher chance of one appearing. Modding a unique depends on the specific item involved."
Getting Started, p39: put this somewhere closer to the various other item mentions (like powerups and consumables)
Getting Started, p40: put this somewhere closer to the various command mentions
Getting Started, extra: missing any mention of artifacts, even if vague. Example: "Artifact - Items of this category are revered as the best in the game. It can only appear on certain special levels, after overcoming a great challenge. There are only two known artifacts so far."
Whew. That's the big section: I'll hit the other areas later. (Introduction has no problems, by the way.)