Another World

Just launch the game and select your resolution from the video options.
The DOS original ran at a 16:10 resolution of 320x200. This version, when running at a 4:3 resolution, letterboxes the picture. When running at a 16:10 resolution, the letterboxing is gone. Both ways, the aspect ratio is correct.

Since the original ran at a widescreen resolution, it seems unlikely that this would have any anomalies from widescreen.
Aspect ratio: Big trouble here. When you run the game at a resolution wider than 16:10, it stretches.
This is one of the very few games with no HUD and no onscreen information display to speak of. Therefore, there is no HUD stretch.
The cut-scenes are numerous, seamless, rendered ingame, and are anamorphic like the gameplay.