You know that expression about what too much of a good thing can be? Trine 4 is a great illustration of that. After the critical failure of Trine 3 (which had a rather short length, and some levels that had to be unlocked with a specific count of collectables gathered throughout the previous stages, but otherwise was a superb game), the developer decided the safest thing to do would be to release a 2D game (like the first two entries; Trine 3 was 2.5D) that had an absolute wagonload of levels, and have all of those levels be very, very long. From the standpoint of 'safest', they were, in fact, probably right. 'Safest' and 'most appropriate' are two very different animals, however. With the first three Trines, there was never a single point during which I or my playmate got bored with the general gameplay as such. With Trine 4, this happened already on the third non-tutorial level, if memory serves. To add insult to injury, one of the last couple unlockable skills for the knight (Magnetic Shield) makes it so you can solve virtually all space-based puzzles using exactly the same method. OP much?
Sad that Frozenbyte were essentially bullied by the reception to the previous Trine into taking such a path with this one.