Where would you add animations? What kinds of animations are there? What should you watch out for? Let's take a look! I'll pick a few of the most interesting and/or common ones and discuss them here.
1. Blinking animations
You know them, where the poor souls on screen need to blink every few seconds to remind us of it. Or blink so little that people forget they're blinking at all. So, for starters, blinking is hard to do right. But there are more reasons why I avoid adding this.
While reading, these sudden movements (especially if the eyes are big) distract my attention from the text. I guess this is because unlike looping animations which you see constantly (rain, snow), blinking has short periods of animations after a period of no animation. Furthermore, when the eyes of an otherwise static character sprite blink, it just makes me more aware of how static the sprite is.
The only times I can remember when they didn't bother me, were when the timing of the blinking was just right or when the eyes of a character weren't all that big. The bigger, the more I notice it.
2. Mouth flaps
If you ignore what she says, this is kinda cool. However, like with blinking, it's hard to get right.
Setting aside the fact that some visual novels don't use voice acting, so matching the lips to the words is harder and a little awkward, it's actually also a lot of work for little gain. To make it look good, you have to use the right frequency and enough frames, or it will just look off.
Having the right frequency prevents it from looking extremely slow or hyperactive, but it's not easy getting it right. Shira Oka, for example, in which the characters were often moving their mouths at incredible speeds
As for frames, like for any kind of animation, you need to draw enough of them. If you only use a frame for mouth-closed and mouth-open, it will look really... silly.
3. Sprite animations
When I say sprite animations, I mean sprites which don't just change poses, but are fully animated as they change poses. This is a really cool addition to a visual novel and a step further than mouth flaps or blinking eyes, but the rose has some nasty thorns as well.
Let's look at uguu-san below for an example.
|I will never exist, sir!|
So, while it may be cool, decent looking and animated sprites will take a lot of work, and that probably means cutting poses in return.
The other reason why you may reconsider using this, is what convinced us of discarding the idea of sprite animations in our current project. Since your characters will be animated, their colouring and lines may become a lot less detailed and refined. As animation quality depends on the consistency of the sprites, it's very hard to use epic highlights, cool shading, layer effects and what not to keep the quality up.
As it's very tough and time-consuming to get it right, most animated characters end up looking more simplistic than a character which wasn't animated at all.
4. Movement of background elements
The fun thing about moving background elements is that it is relatively simple to do, compared to the other examples, and that there are a lot of ways to utilize this one.
For example, translation. Moving clouds from A to B and then starting at A again to loop it, which is not that hard. Add multiple layers with clouds with different sizes and speeds, and you can create depth. Or make use of rotation to let wheels turn around and let grass sway in the wind. However, the moving background items should be drawn onto a different layer, so plan them out in advance.
5. Pans and zooms
Use this. Seriously. Pans are another gem of an easy animation method which makes your visual novel much more dynamic just by moving the camera. You will have to use backgrounds which are broader or higher than your VN's resolution is, but in our opinion it's totally worth it.
The same goes for zooms; you could have one CG for a battle and still make it an epic scene by just throwing in some sound effects and focusing on different parts of the CG, matching the current text (hi there, Fate/Stay Night).
6. Particle effects!
I love this one! Particle effects are simulations of otherwise hard-to-create phenomena by creating many simplistic images; it's commonly used for rain and snow. It's a little trickier than pans and zooms or moving stuff, but these are awesome mood-setting animations.
Well, these are the main ones we wanted to discuss. I think we'll mostly use the last three ourselves, but there are many techniques I haven't covered here (blur, depth of field, etc.). It's a lot of fun to look around and see what you can do to make your visual novel even prettier.
Explore and experiment, I'm sure you'll create some lovely effects!