Jagged Alliance/WMG

Revy and Meltdown were close friends.

 * Both use the expression "Fuckin' A". (Or, in Meltdown's case, "effin'".)
 * Both use a Beretta. (Or Berettas, in Revy's case.)
 * Both are efficient with Guns Akimbo.
 * They're also psychopaths.

Raider is an alternate universe version of Murderface.

 * They're both ugly.
 * They slur words and at times, make no sense.
 * They look similar and sound similar. (Except for the slurring part.)
 * They're also somewhat jerkassed. (For example: Murderface attempts to be sensitive and fails, whereas Raider is a decent merc but gets angry if he does not see combat or try some sort of task, like training militia - it's also implied Raider's more worried about Raven's insurance policy than Raven herself)
 * Ugly? I mean, being a fellow guy, I'm no real judge of male facial appearance, but he doesn't seem ugly. Average appearance, sure, but this is hardly "ugly." I don't recall him slurring his words, but admittedly it has been a while. Though I do recall that weird, deep yet squeaky voice.

Red is either a relative or alternate version of the Demoman

 * That accent...
 * Also, their jobs. Red's more finicky about killing people, however.
 * No, no, no. Spragg and De Groot are just the Salt and Pepper of insane Scottish bombers. They blow up crime.

Scope Sterling is Seras Victorias if she hadn't been sent on that church investigation

 * They're blonde snipers armed with a BFG.
 * Cheerful.
 * British.
 * Seras, decidedly not killing Nazi Zombies and Vampires, was tapped by the SAS after her sniping skills got honed. Changed her name to Sheila and got married.
 * Apparently like killing when they kill enough...