I have only been playing it a day, but here is what I have noticed.
Each character uses the same amount of energy per fight. early fights require1 per character, later stages require 2
so if you focus on one team, you will end up exhausting your good characters, and then having a Secondary squad that is too under-powered.
So I would conclude you should try to get at least 6 characters (2 teams), and level them up evenly.
so to summarize:
- 6 characters, 2 teams. - Each team should have at least 1 character who has heavy damage and good health. if you put all your strong characters on one team, you'd be at the same disadvantage. - try to keep them balanced, and make sure each team has 1 strong fighter. -Try to ensure that each team has at least one character who has a "Power drain" special move. This will prevent your enemies from using their special moves and inflicting heavy damage on you.
Just spent about 30,000 upgrading two characters so their specials have more damage, bought all three cards for both characters (health, energy and damage), Im at the second tower and fighting silver characters with a lot of health who absolutely STILL kick my ass and are around the same level as me...