Originally Spaghetti westerns aren't really a style as such, there were many different styles of films classed as spaghetti westerns, they were originally called spaghetti westerns literally because they were westerns directed by Italian directors.
These films were more common in the 60's and most of the weren't even filmed in Italy (although some were), the most popular place to film them was in southwest America, and North Mexico.
Later spaghetti westerns kind of fell into a rut of typecasting, usually involving a desperado, new to town who falls in with the bad guys, ends up playing them to make money, then finds a local cause to fight the bad guys for, at some point he gets found out by the bad guys and beaten up or nearly killed, then comes back with a "you messed with me, you're going to die" attitude, dramatically kills the bad guys and saves the town, then rides off into the sunset.
More modern spaghetti westerns kind of veered off a little, becoming almost comical, using quirky characters, more whimsical music, and more beatings with less actual deaths.
I would go more for the earlier type of spaghetti western personally, it's far more dramatic, you just need to be able to stick to the ethos, and work out how to create the drama, this would probably be achieved by a lot of cut scenes, for example a over the shoulder view of the bad guy strutting up, a quick shot of the hip and the hero un-catching his holster, maybe flexing his finger, another shot to the heroes face chewing a cigarillo, and so on.
The old fashioned spaghetti western style lends itself very well to heavy amounts of cut scenes and close ups. If you can pull that off and get the atmosphere right, it should be a good game.
As to the graphics style of the game, that video looks pretty awesome, but if you're set on making it in the cartoon style of your video, then making it in a spaghetti western ethos might be the wrong direction, proper spaghetti westerns are very rough, and down to earth, focusing on a more realistic aspect of western society, i would say to get the dramatic feel of spaghetti westerns you would need a more realistic style, less smooth lines, more rough edges, if you know what i mean, you might get away with realistic textured models, pastelizing the colours and adding a cartoon outline, but outright cartoon would just feel wrong for the ethos.
Personally, judging by what you have done so far, i would just cal it a western and drop the spaghetti, it looks really good so far.
Oddly enough, and i have no idea why, but watching your video really makes me want to make a game based on the firefly/serenity universe, no idea why lol.
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