Ok...
There's potential, but it still needs quite a bit of work yet.
The animation looked to stiff. You relly need to smooth it out and make sure the images fit perfectly. Your main character was fireing his pistol without having his finger on the trigger.
The knife was...interesting. The first stab was done well, but the slash looked absolutely horrible, and the knife flew through the air like it was shot from a cannon.
Some blood splatters didn't work. They were darker than the rest and oddly shaped.
The greade effect was good, but the dude blown over your main character changed sprites. This needs fixing.
No speech bubbles. Use speech boxes or actual voice acting. Looks nicer that way :D
And the most important correction: two way action. Have the taco dudes actually fight. That would add length and make it a real madness flash. The taco dudes just stand there like target dummies. Please, if you ignore everything else you must do this one thing.