Platforms: PC
Genre: Platformer?
Estimated year of release: 90s
Graphics/art style: Flat polygonal, early 3D, “eerie”
Notable characters: No idea
Notable gameplay mechanics: a hot air balloon takes the player to platforms in a skybox, either at the start of the game or between levels
Other details: there may have been a puzzle element involving placing bombs, but I could be conflating that with a different game of the area. I remember watching my grandfather play games on his PC and this was one that stuck in my mind due to what I remember to be an eerie/ethereal vibe.