One of the things I like best about SR4 is how the rules have been greatly streamlined and simplified. If you are one of those GM's who likes to keep things quick and simple, SR4 is a vast improvment. It is much easier to do things fast and on the fly, with penalty and bonuses signifignatly easier to asses. And most importantly, threshold is MUCH better way of setting the difficult of a task then TN ever where, especially considering previous editions funky roll breakdowns.

That said, I think SR4 can be made even simpler, and improved by it. Here are a couple of the house rules I have been using to make things simpler to calculate. All these rules have been at least moderatly playtested, so these aren't just random modifications.

#1. No ballistic or impact armor, just plain armor.
SR is just screaming for this simplification IMO. Except for clothing, ever other single part of the game has just one simplified armor rating. Drones, Spirits, Dermal-Plating/Orthoskin. This rather modest simplification eliminates a lot of confusion and is makes things easier on simple-minded players (or those just unfamiliar with the rules). To find the armor rating for clothing, simply average the two rating together, most of the time this results in a armor rating that is one less than the ballistic, and one more than the impact. When dealing with weapons that formerly targeted only impact or balistic armor, they now just target the regular armor. Things that target 1/2 ballistic or impact now target 1/2 the armor rating.

So far the impact of this modification has been rather mild. Unarmed combat is slightly less effective, armed combat slightly more so. However, the advantage of ballistic weapons is curbed by my next rule modification. Also, combined with some other rule modifications, they balance out the various ammo types more effectively.

#2. No AP modifiers for anything.
Calculating and figuring in the effects of AP modifiers takes up precious time and is fairly complicated. Eliminating it greatly simplified and speed-up my play. All fire-arms deal there base damage (4P-6P-Whatever) and the AP modifiers are just ignored. optionally, weapons with AP values greater than -3 can translated into one addition point of damage for every 3. However, we do not play with this optional modification.

This rule helps to balance out the increase in firearm power due to the previous rule. The effect on most pistols and rifles has been mild, while the effect on heavy weapons is considerably greater. However, when the LMG, MMG, and HMG are used in full auto mode with their appropriate compensates the effect is lessened somewhat. I should note that my game these weapons are not very commonly used, nor are heavily armored vehiles often seen.

#3. Minor (common sense) modifiers for ammo.
This goes with the previous homerules. Ammo types that used to add to AP don't. They simply add to the DV as they did previously. APDS now targets HALF the characters armor. Flechette rounds face twice your armor rating.

The effects here have been minor except in the case of Flechette rounds, who have been nurfed pretty badly. The solution my players have found is to make called shots avoiding the armor when necessary, or not to use the rounds against armored targets (duh!). This has balanced out the potential of the various weapons pretty well.

#4. Use the optional rule where every spell is cast at maximum force, do not allow overcasting.
This speeds things way up, as most have probably found. In addition to this, I have player pre-calculate the average level of success for spells like increased iniative, and let them use that for their results if they like (rounding in their favor generally). This speeds up play considerably, but does remove the powerful (but potentially broken) option of overcasting.

#5. Make players spend an edge point to overcast, force it at twice there magic. Double the drain, now physical.
This rule brings back the powerful option of overcasting, but with some increased cost. Making them do it at twice their magic simplifies the calculation (just twice the old drain). Making it cost edge gives it some flavor, as if they are calling on deep reserves to pull the spell off.

In play this option has gone fairly well as an option of last resort for a mage. Honestly I wanted to do away with overcasting all together (force 6 powerbolt is bad enough, thank you), but this option has let my runners have it, when they think they really need it. Avoiding re-caluclaiting the drain for overcast also speeds things up.

#6. Moving is a simple action
Inspired from D&D, moving takes a simple action. This is a pretty fundamental chance, but makes things easier to calculate. No need to split into how many meters a phase or whatever, they just more (or double-move/run) as necessary. Since you can't move and shoot at the same time, those modifiers can be ignored. Some realism is sacrificed in favor of plability. Running and dodging can be combined in the same complex action if you wish. Charging (ala D&D) is also allowed.

In play this has actually worked pretty well. theoretically characters with more passes would end up much faster, but most of my players end up with about the same number of passes anyways. Battles tend to be shootouts behind cover instead of running gun battles, but frankly thats what they were before to. It also makes players tend to fight or flee, few running battles take place.

#7. No stun chart.
Stun and physical damage is handled on the same chart Mechwarrior 2 style. You have the same number of physical boxes as before, you now just use them for both. When you take a stun one you mark the first unwounded/unstuned box with a slash, and when you take a physical wound you mark the first unwounded box with an X, filling in a stun box if necessary. Other effects happen as usual, but double penaltys do not accumulate.

This rule change has also gone very well. Some mages lost a little damage capacity, but generally not that much, just a box or so. Trolls and other high body characters became more difficult to knock out (which makes sense). Wound penalties are much lower (obviously) but this has proved to be a good thing. Before wound penalties accumulated to quickly where a semi-functioning runner (boxes half full) might be unable to do anything effectively (-4~6 dice). Unarmed combat became slightly less effective, but only against people who had lots of boxes, who were tough anyways.

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Well thats about it. So far I'm pretty happy with how it has all worked out in my games. Your thoughts and comments (pro and con) are welcomed. I would also love to here any ways you guys simplify the game.

BTW, first post in a LONG time on this form (had to re-register) so I gave you some content, sorry no elf-porn.