Here is the full list of all 20 Blackjack of Strip achievements.
Unlock armor
Unlock a standard deck of cards
Strip the enemy 50 times in a multiplayer game
Unlock a deck of cards with nude girls
Unlock a deck of cards with mystical girls
Strip the enemy 25 times in a multiplayer game
Unlock Takashi
Unlock Santa
Unlock Snow Maiden
Unlock Yumi
Strip the enemy 10 times in a multiplayer game
Strip the enemy 5 times in a multiplayer game
Strip the enemy 1 time in a multiplayer game
Unlock Dragon
Win in a single player game 10 times
Unlock Mrs santa
Win in a single player game 5 times
Win in a single player game
Read the rules in Russian
Read the rules in English