When the use of cd-roms for games became mainstream in the 90s, there was a massive explosion of people taking advantage of all that extra space by adding full motion video to their games. A lot of great games were released during this time but it became a short lived trend since there were also a lot of bad games released. Having grown up playing a lot of these games, I'm now (mostly unironically) a fan of FMV in games and love seeing what new games are using it on Steam and Itch. While FMV can limit what kind of games can be made, I think it also has advantages. Video of real people or things can possibly help players connect to the story being told and even low budget or bad FMV can be charming. While it sounds intimidating to record something for a game, it doesn't mean it must be a big production and there are a lot of tools to easily add video to your game.

Adventure Game Studio
Adventure Game Studio is a free and open source game engine for making point-and-click adventure games. While most games made with the engine are 3rd person adventure games, the engine can be used in a variety of ways. This excellent tutorial by Space Quest Historian shows how someone who has never used AGS before can make a first-person game that uses FMV. Even if you have no interest in using AGS, there's some good advice in here.

• Anyone can record video for a game as long as you have a smartphone. Making FMV doesn't mean you need to have massive camera, people doing makeup and lighting, and a cast of actors. I'll talk about it later but last year I made a game with my cat and an iPhone.
• Plan all the video you're shooting in advance - Make sure you know everything you'll have to film before you start shooting your game. It will be a massive headache to go back and get more video once you're halfway through coding the game and realize that you forgot to film something.
• Organize your videos - Make sure you have a good folder structure and naming scheme for your videos. If you have a lot of little video clips, it can quickly become overwhelming to figure out what videos are used for what.

Charles Engine for Unity
If you are more interested in doing a Choose Your Own Adventure/branching narrative game, I can recommend the Charles Engine plugin for Unity as an option. The Charles Engine was made by Charles Games, developer of games like Attentat 1942 and Svoboda 1945. I made a very tiny FMV game using this plugin with my cat last year and while I would maybe recommend having an actor less difficult to direct than a cat, making a game with the plugin was very easy and the engine provides an easy to use tool to plot out all the nodes and branching that your interactive story will use. But the plugin can do more than just interactive movies and the tutorial that comes with the plugin has you eventually creating a game set on a fake computer desktop, kind of like making your own version of Her Story.

Narrat
Narrat is a lovely tool for making interactive fiction games, with a layout that seems to be inspired by RPGs like Disco Elysium. But that's not all it can do. The creator of the engine also made A Walk Through the Forest, a short interactive fiction game where you walk on a trail through a forest while the narrator talks about their personal thoughts. Parts of the game can have you looking at video of parts of the trail. Narrat also has integration with Godot if you prefer to work in that engine. Hopefully one of the takeaways from this post is that your game doesn't even need to have people in it, it can just be video of nature or animals.

Twine 
Even Twine can be used to play full motion video. Issue 36 of Wireframe magazine (RIP) has a tutorial on how you can do this. The article's author also has two demos of this on their Itch page. One demo uses footage from the film Plan 9 from Outer Space while the other one recreates the dialog system from one of my favorite games The Beast Within: A Gabriel Knight Mystery.

I hope this post was useful and you'll consider putting video in your next game, whether it's a personal story or a total schlock fest. If there's other tools that you use for this type of thing, please let me know in the comments!