- The Other Darrin: Overlapping with Early-Installment Weirdness, the first game features different voices than the rest. Narrator was voiced there by Rafał Kowal, while Rex and then-unnamed Moles were voiced by Marek Kocot. Due to Kocot moving to Wrocław shortly after the production of Treasure of Pirates wrapped, Rafał Kowal took over the roles of Rex and Moles from the second game onwards. Meanwhile, Narrator from that point is voiced by Grzegorz Wolf instead. Nevertheless, UFO and its two sequels recycled Marek Kocot's lines for Mr. Policeman.
- Screwed by the Lawyers: As with most licensed games, Aidem Media stopped selling all games featuring Reksio (including Przygody Reksia series) after the company's license to use the character expired in January 2016. Don't expect Aidem Media to renew the license, given the fact that the company seems to be currently focused on making flight/driving simulators for mobile OSs (like iPhone and iPad).
- What Could Have Been: On the series' official forum, the creators said that the fifth game was originally planned to be much longer, but due to the pressure from the fans, the release was rushed and many of the ideas were scrapped (the last arc was especially damaged by this - what was meant to be a typical, interactive part was almost completely replaced by cutscenes).
- The Wiki Rule: The series a wiki here (in Polish only).
Trivia / Przygody Reksia