You'd be forgiven for thinking post-credit scenes are reserved for films - especially after the prevalence of them across the MCU - but stick around after some of your favourite titles' wrap and you might find a nice little surprise. In fact, you'll be amazed how many key games feature post-credit content expanding what you just saw.
Post-credit scenes have actually been used in games for decades, and are sometimes locked off until the player has completed certain parameters. For example, completing in a certain time, or by making certain choices. Acting as an incentive for players to appreciate the developers who have worked on said game, there is usually a short scene that serves are a reward.
While many are short scenes that serve as small rewards for hard-working players, more significant post-credit scenes can either be an extension of the story or even setup for a sequel.
There are even a few post-credit scenes that actually make you look at the game in an entirely different way, saving crucial plot developments until the very last moment.