Sadly, I didn't save most of them and I couldn't get the .swf files working when I try to open them with an offline flash player, due to a DRM (or something?). (Because whenever I try to open them, something like "This game is playable on Gotmail only." message appeared.) Then as I said before, the website is not reachable anymore. So, if the games aren't archived somewhere by someone, there's no way to play them, except some well-known ones which are on different flash game websites.
I love the Submachine series and I'm so glad that we have a developer who cares about the series. But what I'm sad about is the Gotmail escape game series. After the EoL of flash player in 2021, the games became unplayable and then I guess the website has been shut down. I'm so sad that I couldn't get to experience each unique game and I'm never going to be. It even has a steam group (which is inactive but still exist) about the games and has each game's links.