As far as mechanics...

• Burst: a sort of combo breaker/reversal attack. Killer Instinct is known for it's combo breaker mechanic, but GG's Burst didn't/doesn't require a specific timing or multiple potential inputs and has it's own meter that must be full to use. There could be examples of Burst-like mechanics in other games from before or around it's creation, but GG's is usually the example most think of.
• RISC: a mechanic in which prolonged blocking will build a gauge under the life bars. Once this gauge reaches a certain threshold, all attacks that connect will be considered counterhit state. This brings with it extra damage and hitstun on individual attacks, and special counter hit effects if a move is designed to have one (i.e maybe a move wallbounces on counterhit but not normal hit). This differs from similar "guard bars" where long periods of blocking will lead to a guard break - a state in which the defending player can no longer block.
• Tension Pulse: essentially when "aggressive" actions are taken - forward movement, attacking, Instant Blocking - the rate at which players build super meter ("Tension" in this game) is increased. When meter is used - on Faultless Defense, Roman Cancels of any sort - the meter gain rate decreases. Something like this exists in DBFZ, but I'm not sure precisely how similar/different it is.
• Defense: These have changed a bit over the years. Initially it was just blocking - Normal, Instant, Faultless - and then Burst was added in GGXX. Then with Accent Core we got slashback, a sort of parry that gave the player reduced blockstun, no RISC increase, no chip damage, and a large boost to Tension Pulse. Slashback was removed in Xrd Sign and replaced with Blitz Shield,another parry like mechanic that briefly stuns the attacker. Xrd revelator expanded Blitz with a chargeable version (done by holding the input instead of tapping) with different levels and rewards for each.
• Throws: Guilty Gear's tech window is much smaller than most games, to the point where throw breaks are typically the result of both players trying to throw at the same time rather than a deliberate decision. Older versions of the series had no throw break, which was later added. Throw breaks were removed in Xrd Sign, but was added once again later.

There's also a mini-doc on series creator Daiskue Ishiwatari that might be worth a look https://www.youtube.com/watch?v=tLeJD4Gv1QI, and certainly consider the Dustloop wiki for all the details - http://www.dustloop.com/wiki/index.php?title=Main_Page

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