If you want to chat with your opponent and leave them messages tap on the icon in the upper right corner or at the bottom of the round screen. When you opponent next log in to play their round they will see your message.
To get the best out of your character you must invest the ISO-8 you collect. For example, if you have the Hulk you can get 'Flawed Health' for 1,000 ISO-8 to give him a +375 health boost. If you get 'Radiant Damage' for 5,000 ISO-8 he will have +120 damage. Combo Gems like Prismatic Defense can be aquired for 30,000 ISO-8 and will give him +750 Health and +11 Stamina.
The Hulk has six different powers tied to his Rage meter which can be unlocked by using ISO-8. Only three powers can be used at a time. These powers range from 'World Breaker' where Hulk smashes the ground to unleash a wave of damage to 'Unmatched Might' where Hulk roars, producing dangerous gamma radiation. Once you have unlocked a power you must remember to keep upgrading it to increase it's overall effectiveness in combat.
If during a fight you need Medkits and Packs you can press the 'Pause' button instead of visiting the store. When you press the 'Pause' button you will be able to select which item you want to buy and return to the fight.