I bought my laptop in 2015 for the sole purpose of work and websurfing, (which it's been perfect for) and as such its specs weren't top of the line even then, and I've never used it for gaming.

Being not very knowledgeable in this regard, I was wondering what games it could run, with the following specs:

CPU: Intel Core i5 5200U @ 2.2GHz

GPU: Nvidia Geforce 820M

RAM: 8GB

(And yes, I know it's basically a potato, haha)

You could probably run 99% of the games on gog.com

2d indies and hentai games. Some 3d games and emulators as well probably.

This should give you a pretty good idea:

https://www.notebookcheck.net/NVIDIA-GeForce-820M.108477.0.html

Mine is from 2016 but you literally have the same specs that I do.
Ehh I dont do PC gaming, so I wouldnt be a good reference, but you can run Diablo 2/3 and WOW for whatever its worth.

Ouch, that GPU is entry level. Perhaps you can play classic PC games or 2D pixelated indies from or on gog.com what The_Liquid_Laser and pervy Yuri senpai said.

I thought hentai games had sophisticated 3D graphics like in the ads, lol

Loll most of them are either VNs or made in rpg maker/unity. There are some super fap worthy ones that you can play in VR though as well as 3d ones that will make your PC moan usually for a lack of optimization... But that's why I have a high end PC

Source engine stuff i.e Half Life 2, Counterstrike Go and less intensive games like Rocket League; on lower resolution and settings at 768p @ mostly over 60fps.

Basically it should be able to run older 7th gen games at 768p and lowish settings.

Try to run Doom Eternal as ultra settings and then invite some friends over and play hot potato with your laptop. Whoever has it when it explodes loses!