Have the mechanics changed at all, or is it still the same?
The mechanics have changed. Drastically. SR4 is, aside from the setting and backstory, just about completely unrecognisable compared to SR1.
Let's take just one thing ... combat with firearms.
First off, your damage tracks weren't attribute-dependant; you had 10 boxes for Physical, and 10 boxes for Stun. Period.
Secondly, damage wasn't measured in a set numbr of boxes; they were measured in Wound Levels.
Light was 1 box,
Medium was 3,
Serious was 6, and
Deadly was 10.
Thirdly,
staging ... that is, modifying damage up (attacker) or down (victi- er, defender). For every X successes in favor of one side or the other, the damage shifted by one category:
(none)<-->(L)<-->(M)<-->(S)<-->(D)<-->(D+1)<-->(D+2)<-->(etc)...
Fourthly, and this was dropped for 2E: ]b\not all weapons staged the same.[/b] Weapon damage was listed as (power)(damage)(staging) ... for example, "6M2" for the Ares Predator IIRC. The power of the weapon, possibly reduced by armor, would be the defender's Target Number (TN). The Damage level was where it all started. And the Staging number was how many Hits you needed, to shift things one step in your favor.
And fifthly:
Target Numbers. In SR4, the TN is always 5, and it's the die pool that gets modified by things like Smartlinks. In SR1, 2, and 3 the die pool was largely static, and the
TN got modified. Starting TN for shooting people was a 4. Smartguns lowered that by 2. Hitting a TN of 7 or higher, meant you had to roll a 6, then roll that same die again (and add the new number to the total) ... the original "rule of six".
So, sometimes that 4L3 gun, might be better than a 5M2. You're going to get lots of successes, and if your foe isn't wearing much armor, he's NOT.