The maze lighting looks pretty nice, and the beveled edges make it look pretty old-school. The sunset should be more even and circular, and the colors should stretch out more so you get a better transition rather than just staircases of color. Also, clouds would make this scene a lot more interesting to look at, since right now there are huge areas of boring flat space.
The owl also is pretty uneven, it'd be a good idea to either make a big circle by hand or use a circle tool to make an even circle. Or if their head isn't a circle, sketch out what their head should look like without the shading. While it's good to start out with cel-shading as I said before, even more important is to have all the segments in the picture strongly constructed. Also adding some kind of surface texture and backlighting to the owl would make it more interesting, since now it, like the sky, is a big lump of solid color with some light at the edge. Being the main character of the game, it's important to make him interesting and fun to look at in the title segment too.
Lastly, composition. The maze lines point toward the sunset, but the castle is slightly offset. This makes the castle less of a focal point, instead the wobbly sun-like light becomes the focal point by virtue of pointing lines and it having the lightest color in the scene. Moving the castle at the point where the labyrinth lines meet makes it a stronger focal point, and if you want to avoid making it super cliche the sun can be moved to the side somewhat.
