The portions in first person and isometric view feel awkward and honestly don't look very good, but more importantly are basically impossible to control with a mouse. The top down view works just fine, so I don't really see the need to change around the basic controls.
Given that it seems like you wanted to make a visual novel, I'm not sure what the point of the RPGMaker combat/movement is. An earlier post says that the combat is intentionally easy (which the final boss even lampshades), so it seems like you'd have an easier time if you swapped to Ren'Py and just made a visual novel, since you could put more of your focus on the rendered scenes. Sticking with RPGMaker, you could also focus the gameplay part of the game on puzzles as well, maybe taking some advantage of having 3 characters with wildly different sizes to get past obstacles.
In terms of the scenes, besides the point about just having more images showing more of what's happening, having a bit more interaction between the different characters in the scene besides just Darx and the main Titan could add some variety. There's only so many ways you can show a tiny guy rubbing himself off on some giant limb/mouth.
Finally, there are altogether too few scenes with the cat familiar. She deserves her own Daz model too!