7. Metro: Last Light - Redemption Ending
In the irradiated and downtrodden world of the Metro series, survival by any means is front and center of your priorities. You will come across people doing whatever it takes to etch out a living and sometimes you'll be faced with choices that would make a regular person's moral compass spin into oblivion.
Shooting, stealing, and coercing becomes a natural part of the gameplay, and for a long old while it was assumed that there was only one ending to Metro: Last Light, until some players looking for a more wholesome experience discovered the Redemption ending.
This ending is actually the canonical one as well which means that players hopping from Last Light to the sequel without it were very confused indeed. In order to net the ending, you needed to make several moral choices that sometimes went against logic (such are removing your precious gas mask in a hostage situation) but it all added up to an ending that rewarded the player for their kindness and humanity.
It's just a shame the game makes no indication of what choices are relevant and there are many instances to go wrong.