I noticed that too. the special ability gauge
is only infinite for Optimus, but that's ONLY
when he's in robot mode. and as for the ultimate attack
(press L3+R3) that doesn't work, at all.
also, the infinite ammo cheat only applies
to the ranged weapons, not the melee weapons
which also use weapon energy. apparently there
are 2 types of melee weapons: energon & physical.
physical require no weapon energy & can be used
infinitely during combat, energon melee weapons
use up weapon energy...and once they're spent,
you cannot use'em unless you replenish their energy meter.