You should go by the numerical level. If there is more than one option, the caster can choose which +1 Level die face to use. It is impossible for Demonic Overlord to rotate +1 Level from Level 2 (since the next level is 4), so it is unaffected. The rulebook covers what a Creature's level is.
Creature Dice that show a Creature Icon can be “summoned.” You must spend Quiddity equal
to the Creature’s level (in the upper left corner of the die face) to summon it.
Why settle for an unofficial FAQ (regardless of how nicely it is laid out):
Shaping Charm - Remember the upper-left number is the Level, so a die currently has a 1 then you can rotate it to any face with a 2, or if it is a 2 you can rotate it to any face with a 3. We don't think you can change to a different face of the same level. We also don't think you can increase the level of a Strong Primordial Ooze.
When an example in the rulebook explains a related rule, you cannot return a creature to the Ready Area on a different die face at the same level.
Shaping Cantrip - Reaction: Cast this Spell to return one of your just destroyed Creatures to your Ready Area (at its same level) instead of putting it in the Used Pile.
Example: Quinn’s beloved Scavenging Goblin has just been destroyed by a mean old Strong Deathdealer. Fortunately, Quinn has a Shaping Cantrip in his Ready Area, which he casts to save his goblin at the last moment! Though he would like to change the goblin to a face with the Burst, he cannot rotate the die, and must return the goblin to his Ready Area with the same (Burstless) face showing. Even though the goblin was saved, the Strong Deathdealer can still use his ability, immediately scoring Glory for his player.