why bro looking different?

That's cuz it's the snowdin memory fight.

So basically snowdin is kinda broken with rooms changing or not being in places they should be, and with amalgamation ghosts as the only enemies.

When you finally enter snowdin town you are forced to go to the north exit where at the end you'll meet sans on a seemingly useless bridge with the wal covered by amalgamates (image 2). Past the bridge everything is white with red shading (like image 1).

In this fight whatever you'll do sans will only say things to papyrus while he's not even there, and that's because you're fighting the memory of him and his fights with papyrus (you kinda taking the papyrus role). If the fight extends longer than what it did the game completely breaks itself.