LogFAQs > #961099696

Episode 4 is kind of bad, in the sense that it feels like a bunch of leftover maps that were rejected from the first release thrown together without really much thought put into balance and difficulty curve (so you often get hard maps followed up by much easier maps). I remember one of the maps around the middle apparently being a bit notorious because there aren't enough ammo pickups to actually kill all the enemies in the stage if you were playing it as a standalone level or starting from scratch.

Though I kind of felt like it was already starting to drop off in episode 3. But that's kind of how shareware release games tend to be. The first, free episode is usually the best overall to bait people into buying it and the rest drop off sharply because everything's basically the same thing but there's maybe 1 new level background/enemy/type/weapon and there's a lot of padding or some more unfair/poorly designed levels get through quality control.

like I enjoy Crystal Caves, but episode 2 has this infamous pixel perfect jump in one of the levels due to the ceiling being too low to get a collectable and then episode 3 it's possible to get soft locked and unable to complete the game if you did the levels in the wrong order and saved after completing them because they forgot to put a barrel or some sort of platform in the hub to get back up to where you were before (so you have to finish those levels last). Well, the recent rerelease did apparently fix those problems though.