The game still played respectably and looked decent before the Legendary Edition came out, but the work on visual effects especially has helped modernize the game. Overall, the changes to Mass Effect 2 aren't incredibly significant. There are a few important gameplay changes as well, and the entire trilogy was unified in a number of aspects. The majority of the work done to Mass Effect 2 for the Legendary Edition was focused on improving the visuals in a myriad of ways. Related: Mass Effect Legendary Edition Review: Like Coming Home
It and the third Mass Effect still held up relatively well, but the gameplay tweaks and visual improvements in the Legendary Edition are much appreciated. Mass Effect 2 was a huge step up from its predecessor even upon its initial release.
When updating the entire trilogy, BioWare's main focus was the first Mass Effect, but the entire trilogy has benefitted greatly from the improvements. All three games were later available on the PS3 and PC, but now the Legendary Edition has remastered the science fiction epic for the PS4 and Xbox One generation. The original Mass Effect released in 2007, originally exclusive to the Xbox 360. New and returning players alike have been taking the Normandy SR-2 across the Milky Way in Mass Effect 2 since the Legendary Edition launched.
