These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
When the helicopter explodes, you clearly see a wire holding a model.
The shootout scene at the beginning is outright laughable: the gunmen and police officers are simply waving their guns with no fire, bullets or sound coming out of it (the sound of machines guns were simply put afterwards during editing, they didn't even thought about the fire and bullets); apparently the filmmaker didn't have the money to buy some blanks. Those who gets shot simply drop to the ground without any visible gunwound or a simple trace of blood. In simple words, some guys storm in an office with toy guns and everyone drops dead for no reason.
A few traces of blood can be seen on some bandages that a few characters wear, this blood is clearly some red artificial stuff that is too bright to be blood.