Yeah, managing to hold against superpower was quite a feat. Unchallengable fighting spirit was the key as well as better training (though not equipment), experience in fighting in woods and snow as well as "General Winter" as we call that bloody cold winter. Numbers were rather hilarious
250,000 men
30 tanks
130 aircraft
vs
1,000,000 men
6,541 tanks
3,800 aircraft
Hardly fair
Tali-Ihantala was one crazy achievement, it was Stalin's elite then after all. And if that battle hadn't been succesful we would've been another soviet controlled puppet nation up to 90's