Alternate Combat System
I'm not actually preparing to implement this in my game, but I thought I'd noodle around with what SWN combat might look like if to-hit was a skill check, and armor functioned as Damage Resistance. The necessary changes are as follows.
Armor Class starts at zero, and is modified up or down by Dexterity. A character with 18 Dexterity has an AC of 2, for example. Shields give +1 to AC as appropriate (see the tech level comparisons in the entry on shields). Field Emitter Panoplies give +4 to AC, and Deflector Arrays give +2. If you are aware of incoming ranged attacks, you may add your Athletics skill rating to your Armor Class against them.
Armor typically grants Damage Resistance. Damage Resistance is subtracted from damage dealt in combat, but does not protect against falling damage. TL4 armor may or may not protect against environmental hazards, at the discretion of the Referee. Damage resistances are as follows:
Leather Jack: 1
Metal Mail: 3
Metal Plate: 5
Armored Undersuit: 2
Woven Body Armor: 3
Combat Field Uniform: 4
Assault Suit: 5
Powered Armor: 6
Field Emitter Panoply: 5
Deflector Array: 4
Advanced weapons still ignore low-tech body armor. Powered Armor and Field Emitter Panoplies still render the wearer impervious to low-tech weapons.
Range is divided into Point Blank, Short, Normal, and Extreme. Point Blank is melee range, around a step or two. Short is up to five meters away. Normal and Extreme are up to those distances as listed in the book for a given weapon. The Crude Pistol has no Normal Range; it jumps straight from Short to Extreme. Point Blank shots are treated as a melee attack, Short range attacks have no modifier, Normal range attacks are at -2 to hit, Extreme range attacks are at -4 to hit.
Melee combat is mutual. When one character attacks an armed adversary who has reason to expect the attack, they both roll the appropriate skill. On a tie, neither takes damage. If the attacker rolls better, he deals damage to the loser. If the defender rolls better, he deals half his normal damage (round down, but no lower than 1 point) to the attacker. A character may use Primitive to attack unarmed, although they do not receive the bonuses that the Unarmed skill gives. A character with Combat/Unarmed of at least 1 is always considered armed and may respond to melee attacks as though having a weapon. Two unarmed characters who are relatively unskilled with unarmed combat can, in fact, flail uselessly at each other for a significant amount of time.
How to Roll to Hit: Roll 2d6 and add your skill and attack bonus, and apply a range modifier if you are using a ranged weapon. Subtract your opponent's Armor Class. You hit on an 8+, and deal damage as normal for your weapon, less their armor's Damage Resistance rating.
Special Results: Natural Boxcars ignore enemy armor.
Likely Effects
I believe this will make Melee combat potentially uglier, in that damage will usually get dealt to somebody. Armor functioning as DR will often cause characters to die more slowly, as they are less likely to be taken out in one big hit. Highly skilled characters (such as Warriors who have moderate levels and substantial weapon skills) will essentially never miss. Some weapons are simply ineffective against heavy armor. My answer to this is to play up the ban on wearing armor in civilization. Nobody should be wearing anything heavier than an armored undersuit in public in civilized places. The Athletics skill becomes much more valuable. Low-level characters will have trouble hitting even an unarmored target at long ranges.
Achievements
I'm inspired here by the work of one of the users of the Stars Without Number G+ Group. If you aren't a Google+ user, by the way, it is OSR heaven out there. Seriously, it's like Facebook for nerd hobbies. The following is probably something I will implement in my own campaign. Essentially, giving out some XP awards encourages the PCs to do things, and giving out XP awards for lots of different things encourages them to try more different stuff. Achievements are much like achievements in videogames. When you do one, note it down. If it's an individual XP award, you get it for doing that thing. If it's a party XP award, the XP goes into the pot and is split among everyone at the end of the adventure. Any given character or party can only receive an award once, as appropriate to the type of award it is. I've split the awards into types in order to help make sure that there are lots of different areas where the PCs can get achievement XP, and again encourage them to branch out.
These numbers probably seem fairly high. That's because I started my PCs out at 4th level, and I wanted them to be large enough to be meaningful. If you were starting from Level 1, it would be entirely appropriate to cut all these numbers in half. There are two awards here that grant 1M XP. Considering that they would both require years of in-game effort and vast fortunes to be expended, I don't consider them imbalanced. They probably shouldn't even be attempted by characters who aren't around Name Level.
Please note that PCs cannot, in my campaign, level more than once per XP award. They'll land 1XP short of gaining that next level.
Combat Achievements
Individual
Kill someone using unarmed combat or an improvised weapon: 1,000
Get dropped to 0HP in combat: 1,000
Use a Gunnery weapon in non-starship combat: 1,000
Party
Destroy an armed, spike-drive equipped space vessel in space combat: 10,000
Kill a named adversary of at least 8HD: 5,000
Engage in a car chase that involves exchanging gunfire and making skill checks. "Car chase" can mean anything from Hovercycles to horses, but not spacecraft: 5,000
Use a nuclear weapon in anger: 10,000
Heist: Carry off a major theft with no shots fired: 10,000
Exploration Achievements
Individual:
Learn a local language unknown to any other PC. Must happen in play for the award to apply. This can be a part of gaining Culture/World 0, but it will probably take a few months spent on-planet: 2,000.
Have something significant named after you: 2,000
Party:
Do complete surveys of at least three unexplored star systems. This involves 24 hours of surveying for each major orbital body, and probably ground excursions to several: 10,000
Name and Colonize an uninhabited world. A functional Colony includes copious supplies and at least 30,000 inhabitants. This will be an extraordinarily serious undertaking in terms of time, attention, and resources, as the PCs are expected to take a hands-on role at every step of the operation: 1M
Participate in a terraforming operation in a significant way: 20,000
Make a substantial contribution to the State and the Academe's efforts to regain access to TL5 technology: 20,000.
Spend at least two weeks continuously inhabiting a TL1, TL0, or uninhabited world, without trips back to the spacecraft or similar: 10,000
Medical Achievements
Individual
Revive a PC or NPC reduced to 0 or less using a Lazarus Patch: 1,000
Use Anagathics for two years straight: 3,000
Party
Deliver high-tech medical supplies to a low-tech world, preferably for humanitarian reasons: 5,000
At least one PC obtains a cybernetic implant: 5,000
Setting & Miscellaneous Achievements
Individual
Spend a month living it up. This means you stay on one world for an entire month, doing not much of anything mechanically relevant. You might be able to train a single skill concurrent to your vacation time, so long as it's one the Referee agrees is not onerous to learn. Your lifestyle cost for this month is 3,000Cr, plus extra for Anagathics. this represents an Elite lifestyle. This can be done on a low-tech world, but it may require additional effort to make sure your resources translate, and the environment must be appropriately luxurious. 1,000.
Spend a month REALLY living it up. As above, you must spend the time on one world, doing nothing of much consequence. Your lifestyle cost for this month is 30,000, plus extra for Anagathics. This represents a Peerless lifestyle. Otherwise as above. Attempting this on worlds below TL3 is very difficult. 10,000.
Party
Obtain a brand new starship superior to your prior one, and begin using it as your primary vessel: 10,000
Wreck a TL1 or lower society of at least 100,000 people, or do proportional damage to a larger civilization. 50,000XP.
Fund a Prometheus Project and raise the TL of a civilization of at least 100,000 people by 1 Tech Level. 1M.
Make a successful, peaceful trade run, that turns a profit and has no Trouble: 5,000XP.
Successfully smuggle substantial illegal cargo: 5,000.
Social Achievements
Individual
Obtain (permanent) Status 3 within the Academe: 2,000
Appear on a major television or radio show: 3,000
Compete in an important local contest or competition of some kind, and make a creditable showing: 2,000
Party
Build your brand. Make a concerted and sustained effort to establish your group as a business concern: 10,000
Thwart the purposes of a major planetary government in a conspicuously heroic fashion: 30,000
Gain an NPC of major power and importance as an ally. Think of high State officials, Navy Admirals, planetary governors, etc: 10,000
Be personally responsible for a major societal shift: 20,000
Maintain a Level 3 Corporate Headquarters, with an appropriate Factor hired and using all 12 Holdings points, for at least a year: 20,000
Campaign Update
The PCs have obtained the services of Spood, a telepathic alien who can translate between them and his own kind. They are currently marching through the ruined city and causing problems. They've annihilated a few monsters using their superior TL4 weapons, and the leaders of the alien tribes are rapidly trying to figure out how to point the PCs at their own problems.
During their perambulations, they found a treasure hoard after fighting a nest of Robber Flies (I am using monsters and treasure as per the Rules Cyclopedia.) This included a number of coins and also an item of jewelry, worth 7,500gp. I explained to them that this would be a huge deal to the locals of a TL1/TL0 world, but that to them it was worth at most a handful of credits as an item of native artwork. Gold and gems are worth practically nothing to spacefarers. See the entry for Trade Metals, SWN Core Book, pg. 40-41.
They have retained it, for possible use as a bribe.
During their perambulations, they found a treasure hoard after fighting a nest of Robber Flies (I am using monsters and treasure as per the Rules Cyclopedia.) This included a number of coins and also an item of jewelry, worth 7,500gp. I explained to them that this would be a huge deal to the locals of a TL1/TL0 world, but that to them it was worth at most a handful of credits as an item of native artwork. Gold and gems are worth practically nothing to spacefarers. See the entry for Trade Metals, SWN Core Book, pg. 40-41.
They have retained it, for possible use as a bribe.