Observations in TNG: "Booby Trap"

The colors of the sunset look much better in HD.

There is a slight framing problem, as thin black lines are visible on the left and the right edge.

The Promellian battlecruiser Cleponji is seen up close in this beautiful camera move past the ship. The miniature was originally created for the horror film "Night of the Creeps". For the appearance on TNG, the model was turned upside down. We can only see the aft end of the ship in the episode, which is why the Fact Files falsely depicts it without the elongated bow section.
Ancient or Mysterious Ships

The miniature later appeared in DS9: "Sanctuary". A shot from that episode was re-used in "Sons of Mogh" and "The Muse". It is only speculation, but the ship may have been Klingon every time it appeared on DS9, although it was not yet green as of "Sanctuary".

We can see see more details of the beautifully detailed Promellian battlecruiser in TNG-R.

Note that the lighting of the Enterprise was changed to match better with the one of the Promellian ship. Also, several more rocks were added to the asteroid field.

The railings on the Promellian bridge previously appeared on the USS Hathaway in "Peak Performance".

The square wall greebles on the back of the consoles were also seen on the walls of the Romulan warbird in season 2's "Contagion".

Costumes like the ones worn by the dead Promellians in this episode (and also by Galek Sar in the video footage) were later worn by the Bre'el IV scientists in "Déjà Q". Recurring background aliens on DS9, additionally with the same make-up as the Promellians, also often wore this type of uniform. The uniform seems to feature a Promellian patch on the sleeve here. This patch was removed for later appearances of the costume.

The chair the dead Promellian sits on is the same type of elusive chair also seen on the bridge and in engineering aboard the Hathaway in "Peak Performance". The same chair appeared in other science fiction films and series too.
Re-Used Props - Furniture

Data's tricorder can be seen nicely here. The "on-switch", present on early models, is noticeable in this shot. Notice how beaten the tricorder looks.

The console features a Promellian logo or signage with an irregularly shaped frame that previously appeared in a similar form on Data's console when he received the distress call and that can be seen on bridge walls and on the uniforms too.

Galek Sar, the captain of the Cleponji, can be seen in a recording. The Promellian make-up was later re-used for a number of background aliens on TNG, in "Generations" and on DS9. As already mentioned, they sometimes even wore the same uniform as the Promellians!
Re-Used Make-ups

The USS Enterprise facing the Promellian battlecruiser in the Orelious asteroid field.

This is a new shot of the alien ship from a different angle, not just a previous one that was flipped or otherwise modified.

Geordi is sitting in front of an animated LCARS display.

This may the first time that "Library Computer Access and Retrieval System" is written out.

More details are legible on these displays in HD.

Display 3: Not only L. Brahms wrote many of those files but other legible names are M. Scott (Scotty), P. Boyce (Dr. Philip Boyce) and A. Probert (Andy Probert).

Display 4: Leah Brahms's middle name is Susan (taken from the actress Susan Gibney).

Display 5: Brahms attended the University of Tomobiki, a reference to the anime series Urusei Yatsura.

One advantage of the expanded corridor set is the fact that the shuttlebay/cargo bay/holodeck doors could now be directly accessed from the main corridor, without the need for a separate short corridor set which was attached to the large double doors, as in seasons 1 and 2. A crew member could now be seen walking from the transporter room or sickbay directly to the shuttlebay, for example.

This wasn't the case here, though: In the first screenshot, the cargo bay/shuttlebay walls can be seen in the background. When Geordi enters the holographic recreation of Drafting Room 5, though, the walls are completely different. Also notice the corridor wall behind the holodeck doors has 4 silver panels, whereas regular corridor walls only have 3 1/2 panels. The comparison screenshot from "Hollow Pursuits" shows what the corridor wall behind the holodeck doors really looks like. This means the set for Drafting Room 5 wasn't built in the space usually occupied by the shuttlebay/cargo bay but rather on a different stage and the corridor seen behind the door was just a dummy and not actually connected to the enlarged corridor set.

An unfinished USS Enterprise-D can be seen through the Drafting Room 5 windows. The drafting room seems to be located within a large spacedock-like space station.

A silver model of a Constitution class ship is visible on one of the desks, it will be seen much better a little later in the episode. The console next to the model first appeared in the tactical lab in "The Emissary" and was also seen in the computer access room in "Evolution".

The matte painting of the structural grid of the Enterprise-D saucer looks different in TNG-R. Although the basic layout of the skeleton is closely based on the original, the new version has hints of detail and structure inside the grid. Additionally, in one shot, a welder's torch can be seen flickering. Finally, a couple of lights were turned on inside the ship, as if crews were at work in other parts of the ship.

The model of another spaceship is can be seen to the left of the Constitution class model, between the two small consoles.

The office chairs appear in several other episodes and are the real-life model Omnific Chair.

Close inspection reveals that there is a second, smaller Constitution-class model (pre-refit) lying in front of the larger one. The model between the two consoles can now be identified as a silver D7 Klingon battlecruiser model, most likely the same one seen in Worf's quarters in "Peak Performance".

The third starship model in the drafting room can be seen here. It is a prototype of the Ertl kit, assembled by Andy Probert. It is an early "test shot" and lacks the surface panel detailing that is present on the final version of the model. Andy was a consultant to Ertl during the development of the kit. The same model likely appeared in Sonny Clemond's guest quarters aboard the USS Enterprise-D in "The Neutral Zone".

The same dilithium crystal was inserted into the warp core in the first season episode "Skin of Evil".

The sequence is just stunning in HD.

The thruster is still missing in the HD version of the episode (see second cap).