1) Character Portrait
In GGAC, this doesn't do much, but in GGAC+R, your portrait will flash red when you are close to getting Bear Stunned.
2) Life Gauge
Your remaining health. In GGAC+R your health bar will be green when at max and will turn yellow as soon as you take any damage. This makes it much easier to tell when a player is getting a perfect.
Your current Tension (super meter). The Tension Gauge has a "pulse" that you can watch to tell how close/far you are to getting Negative Penalty; the slower the pulse, the closer you are to Negative Penalty.
4) Guard Gauge
The Guard Gauge goes up as you block attacks and goes down over time or as you get hit. Once it is raised high enough, the bar will flash and any hit taken will automatically become a counter hit!
5) Burst Gauge
Burst Gauge. Bursts become available when full.
6) Character Specific Gauges
Character specific resources will be displayed here. Examples of this include Johnny's coins and Mist Level; Eddie's Shadow Meter; and A.B.A's Blood Packs and Moroha Meter. These meters used to be up by the character's life bar, but was moved down in GGAC+R.
Each round has a set time limit. If the timer reaches zero, then the character with the most life is the winner of the round.
8) Round Counter
Each round you win will be tallied up here. Usual matches are decided by best of 3 rounds, but can be adjusted in the settings.
The combo counter. Notice that during an invalid combo, the word BEAT turns dark. In GGAC+R, the invalid hit will also show below BEAT.