Two email marketing techniques

emails are a method of communicating with people, this can include potential interest in your games.

A practice that used to be done (that is now ILLEGAL!!!) is called "cold" emails.
Now this is not saying "an email has a temperature", but reflects on the term "cold-calling" where someone would show up unannounced and start trying to sell someone something. The term cold being they are not warming someone up, it can be very abrupt and incredibly annoying if done persistently.  What used to be done is people (or bots) could send emails to anyone and it could contain anything, including an advert for a game. From one perspective this is great as it opens the potential audience to anyone who has an email. another perspective is you can get emails from Anyone, not all of these were just little developers making innocent games though as it could also be malware. This is why it is common for emails to have a section labelled "junk", as they have AI that filters through the different topics and marks repeat emails as spam.

Now you may be wondering  "but if its illegal can I send emails to people?" The answer is yes - sort of.
If you are spamming people, No that's for one just unnecessary, but also goes against a few laws in europe.
However you can send emails to companies PROVIDED they are willing to receive such emails and have told you so directly (would advise getting this in writing).

A different practice (which is LEGAL) is to ask customers or those interested in the game to join a "mailing list"/ "newsletter". This is basically a way of asking permission by the user to send them emails regarding the game - This does NOT mean you spam them all the time or you get to email them all the time, as that's just bad business practices. Generally you could send them an email (or maybe a couple if they were all important and can't be put in 1 email). You want to be Precise with your choice of words, and don't make the email an Encyclopaedia , keeo it short sweet and understandable. the phrase "a picture says a thousand words" comes to mind and is very true for emails, you can tell a lot of information to someone in an image, but too many can look cluttered.

an example i will put here is "Immortals Fenyx Rising". https://www.ubisoft.com/en-gb/game/immortals-fenyx-rising
personally i think this is a great example of a good website, it keeps things simple and easy to read, we would want something similar in our emails. (this may get edited out in future as this is Ubisoft's product not mine)