Indie game released today on Steam.
Steam product page for Trine
It looks to be native 16:9, based off the menu and the logo (compared against the official logo).
Menu screen
16:9 native
16:10 = 16:9 view but stretched to 16:10
4:3 = 16:9 view squished to 4:3
4:3
16:10
16:9
Cutscenes
16:9, anamorphic for everything else
4:3
16:10
16:9
Loading screen
16:9 native
16:10 = 16:9 view but stretched to 16:10
4:3 = Hor- and stretched vertically
4:3
16:10
16:9
Gameplay
>16:9 = Hor+
<16:9 = Hor-
4:3
16:10
16:9