So I've just found out that this and Seed of Evil are part of a sort of collection along with Miss Lisette's Assassin Maid. I've played and almost 100% SoE, and I'm just now starting Key to the Egg here. Is it worth going back and checking out MLAM first? Or has it aged poorly and not really connected enough?
Hmm, do whatever you want really. Though, you'll find the MC of MLAN and a person close to that mc in Serafina game and they have some little story. And yes, the stories follow each other. If we only take the games that are here, the chronological order (which is also the order of release) is :
Escape from Wombraid Maze -> Seed of Evil -> Miss Lisette's Assassin Maid -> Serafina and the Key to the Egg
You have to note it's only the games here, because there's another game that the dev will release and that game is set years before Escape from Wombraid Maze happens, and explain a lot of things. Though, we will have to wait for it to be translated.
Also, in their ci-en, they posted the chronological order of the games and stories (There's little stories posted in ci-en to complement the games) so it's pretty useful.
To finish for the 4 games we have atm, for example in Seed of Evil you will encounter a character in Escape from Wombraid Maze. It's to say, all the games are connected one way or another even if it's just some text.
So if you really care for all the story, you know what to do.