All combat is team based, meaning you choose a partner and battle out against another team of two fighters. The difference here from other tag battle style games is that the round is over if any one fighter is defeated — meaning you really need to pay attention to your health and swap out strategically. There is also a customization system in the form of the Gem System. Each fighter can equip up to three gems and they give if/and bonuses for a limited time. Hit with 4 super moves in a round and get +10% strength for 15 seconds as an example. These are not permanent power-ups and I found that many of the benefits happened accidentally because you tend to forget what gems you have installed. A savvy player, however, could quite easily use these as a strategy though to get a key advantage when they need it.
The depth doesn’t stop there of course with many super moves and attacks for each fighter as well as a number of advanced features. Features like Cross Assaults that have both players onscreen or Pandora Mode giving a huge boost in strength for a limited time before you automatically die being key examples that add a nice depth to the title. There are a few game modes as well such as Arcade (with the option to be automatically pulled into an online match), Training mode (which is very detailed and at times overwhelming) and a Challenge mode that gives specific criteria to meet in order to move on.
Speaking of online it is actually very well done, I left the option on to be pulled into online matches and had quite a few encounters. The game loads up very well and lag was minimal, the addition of gems doesn't really affect balance (even though you will be able to buy new ones) making the matches enjoyable, even though I lost more than I won.
Street Fighter X Tekken has no shortage of options for customizing gem layouts or even color schemes for the fighters, but they are implemented in a menu system that is archaic and counter-intuitive. Just starting a fight with a team you want to look and act a specific way is an arduous affair and that is a real shame because the game really deserves to be quickly accessible in order to maintain the momentum generated in the actual fighting portions.