Here is the full list of all 22 Tarantula Virus achievements.
Kill 1000 enemies
Kill 100 enemies
Kill 10 enemies
Die
Defeat a Boss
Defeat 5 Bosses
Defeat 10 Bosses
Beat the game with Basic
Beat the game with The Tank
Beat the game with Speedy
Beat the game with Astral Blade
Beat the game on hard difficulty
Unlock last level
Upgrade set of items
Buy an item from shop
Buy some items from shop
Defeat Tarantula Virus
Defeat Tarantula Virus with all the characters
Beat the game with shopkeeper's son
Beat the game with abaddos
Unlock Shopkeeper's son
Unlock Abaddos