01. Rare Star: Unlock every RARE RARITY character
02. Epic Star: Unlock every EPIC RARITY character
03. Legendary Star: Unlock every LEGENDARY RARITY character
04. Mythic Star: Unlock every MYTHIC RARITY character
05. Secret Star: Unlock both SECRET RARITY characters (Jevil & Spamton)

And now for the star that ACTUALLY requires a guide...
06. Easter Egg Star: Trigger every EASTER EGG/SECRET
These easter eggs are the following:
-April 2012 (when viewing Card Castle on the menu, type "april")
-KEYGEN (when viewing Spamton on the menu, type "KEYGEN")
-Press F1 for help (also when viewing Spamton, press the "F" key and then "1". by that, I mean the letter and then the number separately, NOT the actual F1 key.)
-The Original Starwalker (type "original" while on the menu)
NOTE: you can do these in any order

And that's all of them! If you've done everything, you should have all six Completion Stars!

[I'll start working on a small quality-of-life update soon, so stay tuned for that! Thanks for playing!]
[PS: It's out right now!]