Challenges are an alternate game-mode available in the game. A challenge has a shorter game-session (covering only 5 levels) but adds different rules to the game depending on the challenge.
Challenges are played without the use of Buff cards.
The Dark #
All levels are covered in darkness, giving you minimum visibility.
You’ll only encounter spider-like creatures and critters and no other aliens.
The game won’t give you any shield-cards for your deck.
No Tech #
The game won’t give you any tech-cards for your deck.
The Martians #
You’ll only encounter martian enemies in all the levels.
Low on Cards #
You start with just 12 cards, and a deck size of 32 maximum.
Pirates a-hoy! #
You’ll only encounter space pirates enemies in all the levels.
Empty handed #
You start with no cards and a deck size of only 16 cards.