Keep a lame so cutthroat
By using cutthroat, he can be using a play on words as in making other rappers commit suicide and/or using its definition as someone whose violent or murderous.
This relates back to charge it to the game.
He’s making a big impact on the industry while making other lame rappers cutthroat, meaning he’s basically shitting on other lame rappers and making ‘em angry and envious. Or he can be using cutthroat as in literally making lame rappers cutthroat (suicidal).
Referring to the last line, if it is"Gacy them haters". John Wayne Gacy was a serial killer who often cut victims' throats.
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