Screen Rotation (TATE mode)

[AlienHuntinYeti]

I'm trying to play Downwell on a 2nd monitor rotated to portrait for TATE mode. I see screenshots of people playing it perfectly, but for some reason when I try to play it like this my screen is scrunched in real tight, only using maybe 1/5 of the screen at most, with gigantic black vertical bars taking up the rest. Normally I'd guess that's a resolution issue but it seems odd to be scrunched THAT far, it seems like it's stretching to fill vertically but leaving it normal horizontally.

How do I get the game to fill the entire monitor like I see on screenshots of phones, arcade cabinets, etc? In case it is a resolution issue, I'm playing at 1440x2560

EDIT: I can get my game to display correctly on the 2nd monitor if I make it my primary monitor. I'm able to do this in game, then once it displays at the right resolution I can change my primary monitor back and it will keep the right display resolution. This is not ideal, but at least it's displaying right now. I'm starting to get the feeling this may be due to my primary monitor being an ultrawide...

Anyone know a way I can get the game to display right without having to jump through those hoops? Maybe a launch option or something?

[AlienHuntinYeti]

I saw someone else is having this issue too

https://steamcommunity.com/app/360740/discussions/0/4199112724329541562/