In Spiral Knights, one achievement many gamers are looking to complete is how to hit an opponent with a snowball. The task is very easy and really can be done shortly after the tutorial. I do recommend finishing out the tutorial, but it really isn't technically needed to actually get the achievement. However, you need 200 credits within the game to actually be able to go into what is called a "Lockdown", pretty much two teams fighting each other for positions on a small map. So you might as well do the tutorial and build up some credits, then do the first dungeon and you should have enough to enter into a lockdown.
Once in the Lockdown, your going to have to choose a build out of the three platforms located directly in front of you when you enter. Once done, walk out of the locker room and notice the piles of snow located right outside. Grab them with the action button, usually the right mouse button, and then when you see and enemy player, point your mouse at them and hit the action button again(right mouse button) and if your successfull, they will turn into a snowman and unlock the achievement. Don't worry if you miss, as the snowballs are spread out across the map and respond ever so often to give you multiple chances at getting the achievement.
So in summary: