Probably over a decade ago they did a cross promotion with TF2 when TF2 was doing that sort of thing for unlocking exclusive hats.

If I remember right… You got some extra starting gear for being a TF2 player, had to play up through a certain point in the starting quests or for a few hours, and then you got the default starter Spiral Knight helmet as a hat for TF2. I planned on just doing the minimum and getting back to PUTTIN A DISPENSER HERE, but I didn’t end up going back to TF2 that night. That said, I think I only played Spiral Knights once or twice more. Couldn’t even get my TF2 playing friends to join me on it just to get them the hat.