I'm afraid I've also started on projects that I never finished off. Most of those were maps tough... Almost half the disc space on my computer is unfinished .vmf files.
Anyway, some mods I started but never finished:
Mod name: Kliener Life
Details:
When I first got my hands on Half-Life: Uplink, I immediatly fell in love with this entire game series. So I decided to start my own mod, before I even bought the game! I only had the tetures, a few models, just the sound included with Uplink, and the old, crappy Uplink dlls. I didn't really plan it very far, but I think I made this the general story line:
You play as dr. Isaac Kleiner (the guy from HL2) during the Black Mesa incident. You start in some sort of room with beds in the desert, walk out of the doors and...
Reason of cancellation:
... There it stopped. I had no more ideas. So I went back to Portal 2 mapping and forgot about Half-Life for a few months.
Mod name: Concept's Choice
Details: It was basicly supposed to be a sort of my version of "The Stanley Parable".
Reason of cancellation I figured no one wanted to play a cheap rip-off of "The Stanley Parable", and I didn't have a voice actor for the narrator.
Mod name: Portal: Escape
Details: Was supposed to be just another Portal game: You solve the tests, you escape the computer.
Reason of cancellation: I got bored and leaved.
Mod name: Test subject 40291
Details: Was supposed to be the sequel of "Portal: Escape".
Reason of cancellation: There's two main reasons. 1, Portal: Escape got cancelled. 2, there's no native support for Portal 2 mods.
Mod name: Unlimited: Source
Details: Unlimited was supposed to be a sort of open-world exploration game set in the HL2 universe. You started in a cafe fighting some CP units. After that, you were to explore the world and... Simply do stuff. Whatever you did was to have consequences, like you could either be friends with the vortigaunts, or you could declare war with the rebels, or extinct the combine.
Reason of cancellation: It really only reached planning stage as back then I wasn't as good at mapping as I am now, and the planned size of the project discouraged me.
Mod name: The Delta Project
Details: It was supposed to be some sort of puzzle horror game.
Reason of cancellation: I don't really like horror games (I don't count Half-Life as a horror game) and had never played one of the theme I was looking for. I simply didn't have enough at the time, and I probably don't have now.
Mod name: Unnamed. It's "sourcemods" folder was named "game1"
Details: Some sort of TF2-art style stealth game with an intrigue story.
Reason of cancellation: I was developing this with some guy, but we wanted different things, and eventually we both lost interest in the mod.
That's all for this time. I'll make sure to post here everytime I decide to cancel a mod.
I might take up development of any of this mods at any time.