Generally speaking, before you do this, you need to place each part of the separate actions in categories, such as jumping or crouching, and after placing the pictures in each separate area, organize the order and play them together by connecting the separate axes through a master control, as if it looks as if the protagonist's movements from crouching to jumping appear to be done together at the same time.
This may look like an animation in the game, but it's actually the result of countless images stitched together.
This is part of the production style of the artist “atera”, who was keen to create these differences in detail and eventually merge them together for playback, which has the advantage that the animation is slightly different every time you watch it, because he designed different movements in the script. left hand the first time you watch it, then the next time you watch it it might be the right hand. (That's just an example, of course.)
If the game was its own work, it would be fine because he knew exactly how to design it, but if we try to imitate its style, it will be very difficult.
First of all, you have to make sure that the movements of the pictures are smooth and not jumbled together, which requires a lot of skill and experience, and along with that, the number of pictures needed is huge, as “Rumia” already has 97 CG pictures for the events alone. These images had to be placed and stitched together repeatedly to get a complete animation.
It's not a problem to put them together correctly, as the original author's data file retains the framework for placing the CGs, so it's just a matter of placing them one by one. This part may sound convenient, but it's a tedious and boring process, and you have to concentrate on it, as placing the wrong one makes a very noticeable difference.
Creating new and original CGs can be a bit of a challenge for both Eroism and the illustrator, because at that point there's no data from the original author to use as a reference .....
Lastly, the length of the playback animation, in the short case it's played 6 times, while in normal mode it's doubled (keep in mind that in the original version, all the events can't be skipped ..... So you should understand how long it will be .....)