La Forge tells O'brien "another minute, and we'd both be fossils." Data replies " Not precisely Geordi, true fossilization requires several millennia." Data's statement is false. While at the time of filming, it may still have been believed so, it has been proven that fossilization can happen in a very short time. Experiments have show fossilization occurring in as short as a few hours. It depends on the right chemical conditions, not time.
O'Brien says, "The transporter has detected unidentified microbes in Commander Riker's body." In reality, any time they visited any world with any life on it, if they so much as breathed the air, they would have unidentified microbes in their bodies.
As the doctor puts the probes into Riker's head, we see that the probes are actually telescoping in on themselves. However, the intention would obviously not be to stick metal rods inside his brain as this would cause profuse bleeding and death. The intention of the rods is to deliver electrical stimuli to certain parts of Riker's head as a non-invasive procedure.
Pulaski discovers evoking bad memories helps with slowing down and eventually killing the virus that invades Riker's body. Yet, Troi is seen stroking and caressing his hand, which shouldn't evoke bad memories at all. However, Riker is unconscious when she does this so would not be aware of it. Troi is holding his hand because she doesn't want to lose him.
Initially, while Riker is lying in sickbay, he has his uniform on. But when Dr. Pulaski decides to insert probes into his head, and just his head, he has had his uniform removed. However, by this time Riker has fallen into a coma and his uniform was probably removed as a surgical precaution in case the doctor had to operate.
Riker appears to blink even though he's supposed to be unconscious. You can see this after the infection has been eradicated from his system.
Geordi and Data beam down to the planet to obtain a sample of whatever organism infected Riker. Data suggests he go alone as it is likely Geordi will be more vulnerable to a similar infection, but Geordi insists on going as he knows exactly where Riker was when he got infected. Despite this incredibly high risk situation, Geordi wears no protective clothing at all. Furthermore, when he finds the organism, which is part of a vine, he simply picks it up using tongs and proceeds to beam back up to the Enterprise still holding it in his hand. Considering the clear and present danger, an experienced officer like Geordi should be wearing a protective suit and gloves, and should place the organism in a secure container of some kind.
When Geordi and Data beam back down to the jungle, Data reports that his scanner detects no animal life within 50 kilometers, despite the fact that insect and bird noises are heard in the background.
In one of the clips where they are orbiting the alien world, they show the state of Michigan.
In The Battle (1987), Dr. Crusher claims 24th-century science "...has mapped the brain." Despite this, Dr. Pulaski doesn't understand the endorphins the brain produces under different circumstances.
Riker sees things in flashback that he couldn't possibly remember, like scenes aboard the Enterprise while he's off ship. He also sees the test sequence put to Data in The Schizoid Man (1989). He even sees subtitles in flashback at one point.
Dr Pulaski keeps talking about bringing the "growth rate" down and when she does, she stops or shows down "treatment". The pathogen is still present even when the growth rate is 0% - treatment must continue at the same aggression level until the pathogen is gone else the growth rate will just go right back up.