Quote: "Idea 1: a squad based terrorist fighting game."
I personally like to be a one man show in games but there seems to be a fashion that most modern games have allies for the player to interact with. Not my cup of tea but might work for many other gamers. There are some cool allie scripts around so give it a go.
Quote: "idea 2: a multiplayer game using a class system etc."
I don't see how you build the classes in FPSC but with the variable mods popping up, who knows.
Quote: "dea 3: a haunted mansion game."
This is a bit unspecific. If you like that kind of stuff, look at penumbra!!!
Quote: "idea 4: a platform/adventure like game. similar to tomb raider."
Tomb Raider is third person and would suffer if translatet to ego perspective, i think. But being an Adventure gamer myself i would definitely play any sort of it.
Quote: "idea 5: a game based on classic arcade games (pacman-jetpack etc.)"
well...that sounds far out but on the other hand, pacman with guns, why not
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I am Jacks complete lack of surprise.