When West picks up the cat in the basement and drops it, it is a fake cat, the cat hasn't been dead long enough for rigor mortis to have set in to keep it in that position, or to cause the clunking noise the cat makes on impact with the table.
The university where all the action takes place is "Miskatonic". When West is reanimating the dead cat Rufus, there is a close-up of a bottle of chemicals from the university, spelled "Misketonic", with an 'e'.
When Dr. Halsey is killed, two of the fingers on his right hand are bitten off by a re-animated corpse. Later in the film in the padded cell, Dr. Halsey places his right hand on a wall, and all his five fingers are showing.
At the end of the movie, when Megan has died and has been disconnected from the equipment, she has her chest exposed. Dan is standing over her. In the next shot, when Dan comes closer to kiss her, her breasts are covered by her shirt.
In the very first sequence two signs can be seen next to the locked door. The first one reads 'Dr. Gruber Ghirurg'. The word 'Ghirurg' doesn't exist in German. The correct spelling is 'Chirurg' ('surgeon'). The sign below shows the three lines 'GEHIRN FORSCHUNGSL LABOR' ('brain research laboratory'). The first 'L' doesn't belong there. And as 'Gehirnforschungslabor' is in fact one word in German it should be hyphenated when wrapped.
We see West shoving the drill through the cadaver's back and exiting his chest. The chest itself is a fake with the actor playing the cadaver holding on to it and shoving the drill through himself. We see this for ourselves when the two actors accidentally lift the fake chest high enough to reveal the real body underneath.
When Doctor Carl Hill (David Gale) instructs the hospital orderlies to restrain the crazed, "re-animated" Dean Halsey, they tackle him hard into the wall of the "security chamber", which bends and wobbles and clearly behaves like the false wall of a movie set.