Don't know if this is a cheat or not, but I've noticed that some players have the Bomber aircraft and each time they pick up health it adds to their own, despite it already being full.
This results in their health getting darker.
Is this correct and supposed to happen? It makes the game almost impossible. Against the majority of bombers, a sustained attack (by my own bomber) can take them out. But every now and then there's a player whose health just seems to keep rising and I can unload every round I have (from full payload) and they just keep going.
In comparison, no matter how many health coins I collect with my own bomber, the first impact takes my health down a notch.