Talk:Upgrade/@comment-24971913-20150118114524/@comment-25435121-20150119035447

it's hardly any effort to get a card to lvl 40... if you have enough metal slime to waste on leveling, you shouldn't care about the few extra N or Slime to get it to lvl 40.

If you do care that much, then you shouldn't be using a Metal Slime, you should be using generic R cards and saving the Metal Slime to create a Metal Girl so you can buy arcana.