thx to FlyAnvil (and JMAA) for answering to my little question about the run button. See, in most top-down shooter run is a default feature. here, you must indeed buy it first, under "agility" in upgrades.
if my name was innapropriate, then you should say it on the char creation ... and not letting people buy gems if you intend to permaban them. assholes.
look for ability "Agility": [Shift]