"Sir! This hole appears to be the only exit from this sealed building. Should I keep an eye on it?" "No! Stay here and stare at this corner where there is completely no cover!"
For easy game completion, invest in weapons. Get the revolver with both its' upgrades then save money for the assault rifle. When you get that, the game is pretty much over.
The 5k score on hardcore mode isn't difficult to accomplish. I did it on Sewer by barricading myself in that little gap at the right side of the map and constantly shooting acid bombs outside in which my dumb@ss enemies kept walking into x)
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