A deep technical comparison shows:
The prefix "IGG" refers to IGG Games, a well-known third-party website that provides free downloads of video games. The presence of this tag on the filename indicates that this specific copy was likely obtained outside of official channels like Steam or the Humble Bundle.
During the era of v0.5.5 (circa 2015-2016), BeamNG.drive was in a unique position. It was a tech demo that had gone viral, famous for its revolutionary soft-body physics engine—the "Beam" system. Because the game was often unstable and heavily CPU-dependent, many users sought out these repacked versions to test if their hardware could handle the simulation before buying, or simply to experience the novelty of realistic crashes without cost. However, downloading this version often came with risks typical of the era: missing files, potential malware injection, or the inability to update the game.
If you want to experience BeamNG.drive v0.5.5 specifically out of nostalgia or hardware limitations, do not use the IGG version. Instead: