Multiverser

The game has a mechanic whereby you decide for yourself how you will develop your character during each game:

Eventually there will be about 150 skills in the game possibly more
Unlock all 15 characters and face the dangers that lurk in the multiverse
At the start of each game you buy skills from the available pool, experiment which set will work best in a given situation
Develop your characters
Discover and defeat all the bosses
Get all the achievements