Marcos,
I hope you're sitting down. First, your puzzle has 80 words. The standard for 15x15 themeless is 72. Even for 15x15 themed, it's 78.
Second, the only interesting long answers (IMO) were WILL POWER and JIGSAW PUZZLE. The other ones of similar length didn't do it for me. ULNA FRACTURE is rather unpleasant. I personally don't know who MARIA CALLAS is. That said, I'm a terrible judge of what constitutes valid interesting cultural fill. I'll leave it to someone else to voice their opinion on that.
Third, way too much glue and partial phrases for a themeless:
OERS - bizarre plural
A WASTE / LENDS A / ON OR / A SNIT / THE AIR - 5 long partial phrases
COMIN - what's that?
IRREG - short for irregular?
JSA - what's that?
UPSY - what's that?
SHMO - it's Schmo, not SHMO. A variation of an already made up name?
AGEDOR - is that a thing? If so, you can't use "age" in the clue
WIZ / WHIZ / QUIZ - all very similar entries, crossing each other no less
Sorry Marcos, it's back to the drawing board if I were you.
Julian