Super Mario Wiki Steam group

he probably went into one of those achievement servers

alternatively, you can also check the time at which he earned the achievements to see if he did do that, which he likely did, considering he barely started playing tf2 like a week ago
 
Almost all of them were collected at exactly 1:41PM Australian EST today. The little twerp hacked and tried to show it off as legitimate skill.
 
Your honor can only be restored by defeating me in a 1v1 Soldier duel to 25 points. If you win, you will be respected among our community. If I win, you owe me both of your kidneys.
 
no fucking way you milked all of those in such a short time

and achievement servers are for pussies anyway, real men get achievements through playing proper servers
 
Actually, I'm most certain it's Valve's game, not yours, and I'm sure they're not fond of people cheating their way out of achievements.

Besides, if you're going to cheat to get achievements, then it's not much of an achievement, now is it?
 
then why the hell were you showing off your achievements just before if you don't really care about them
 
I didn't get all of them yet, I just need to play Doomsday matches more

Also you know that I can delete achievement any time