why is "for" needed here?
The "for" means "in order to" and the "at" is here to indicate that it is the infinitive form of the "at lege" verb.
You can see this sentence as :
"They are coming in order to play".
"De kommer for at lege".
Why not "til at"?
what is the difference between 'for at lege' and 'til at lege' ?
What is the difference between lege and spille? Why lege here and not spille?
"Lege" is the past for of "leger," which is essentially free play. "Spille," past tense of "spiller," is used when playing a game or structured activity.
It's not past tense it's the infinitive, 'at lege' - 'to play'
Past tense would be 'legede' and 'spillede' - 'played'.
So if past tense why isnt it they came to play