Can I beat Sans Undertale and still get a refund?

Is it possible to buy Undertale, play through the entire game and beat the hardest bosses, and still be able to refund the game on Steam?~~~Music - Undertale

Greeting Card

Undertale: I beat sans. | Greeting Card

Sans/In Battle, Undertale Wiki

Undertale: I beat sans. Sticker for Sale by Bingdom

You can't say I'm wrong, Cause then you'd be a liar : r/Undertale

Essential T-Shirt

Undertale: I beat sans. | Essential T-Shirt

AFTER BEING DEFEATED SANS RETURNS!!

Sans, Undertale Wiki

Checkmate — I loved everything about Sans, but there's

Undertale: I beat sans. Essential T-Shirt for Sale by Bingdom