itch.io

If you’re on Windows 10, you can use the XBox Bar:

1. Press Win+G to call it.
2. Press the Record button (full circle).
3. Click on your game’s window; the recording will start.
4. When done, either close the game’s window or press Stop recording.
5. You should now have a.mp4 file. You can use it as is, or find an online converter to gif.