One unique feature is the blend of different power systems. Worm has its own set of superpowers and Watchdog may have different kinds of abilities or technologies. In the fanfic, these can combine in creative ways.
Well, 'A New World Order' is another great one. In this fanfic, the main characters from Worm and Watchdog are forced to collaborate to face a common, greater threat that endangers both of their worlds. It has a lot of action and character development.
I'm not sure specifically. There are a vast number of fanfics out there in the 'Worm' fandom. You could try searching on popular fanfic platforms like Archive of Our Own (AO3) or FanFiction.net. Maybe use the full title if you can find it more accurately, or search for key elements like 'worm taylor' and 'the mercenary' to see if it pops up.
The uniqueness of 'worm taylor is x fanfic' could lie in the way it reimagines Taylor's character in relation to 'x'. If 'x' is a concept or another character, it can create really interesting new storylines and character dynamics.
A theme of growth could be present. Maybe Taylor helps Dennis Worm overcome some challenges, and in the process, they both grow as characters. For example, Taylor could teach Dennis Worm about facing fears, and in turn, Dennis Worm could show Taylor a different perspective on life, leading to their personal development.
One idea could be to have Taylor from 'Worm' end up in the 'Fate' universe and have to deal with the Grail War. Maybe she forms a pact with a Servant who is similar to one of her powers in 'Worm'.
I'm not sure specifically as there could be many 'watchdog game stories'. It might be about a watchdog in a game who has to protect something, like a building or a character. Maybe it involves the watchdog facing various challenges and enemies while on its guarding duty.
One main theme is the clash of different worlds. 'Worm' has a more urban, superpower - filled setting, while 'Gravity Falls' is a small, mystery - ridden town. When they cross over, it's about how these two very different environments and the characters within them interact.
I'm sorry, I'm not aware of any specific 'Taylor x Dennis Worm fanfic'. You could try searching on popular fanfic websites like Archive of Our Own or FanFiction.net.
Perhaps a fanfic where the Patriots from Metal Gear somehow gain knowledge of the Worm universe and attempt to control it. They could start by kidnapping certain parahumans and trying to weaponize their powers. Meanwhile, the heroes in the Worm world would have to figure out how to combat an enemy that is so technologically advanced and has such a complex understanding of control and manipulation.