Each creature you control with a level counter on it gets +2/+2.
No one spoke. There was no need. The threat of the Eldrazi presented a simple choice: lay down your weapons and die for nothing, or hold them fast and die for something.
2010-06-15
Each creature you control with a level counter on it gets just +2/+2, regardless of how many level counters it has. It doesn't get the bonus for each counter.
2010-06-15
Time of Heroes affects any creature you control with a level counter on it, not just levelers. (Of course, it's pretty hard to get level counters onto a creature that's not a leveler, but it can be done with copy effects, Fate Transfer, or Quicksilver Elemental, among other possibilities.)