Hey,
Thank you Matt for your advice. I know it is an hard problem (over 2^100 states if we want to solve it exactly, without taking into account moving objects).
However I have some ideas for a cost function that take into account wall clips (not an optimal one since it will not always be a lower bound of the real distance, but... maybe good enough?).
As you suggested, I have planned to reduce drastically the search space by collapsing down states that are "almost equivalent".
For now I am focusing on asymptotic optimisations. I will see later for other optimisations and multicore support.
I finally managed to simulate the physics of Kururin (except the life system and the moving objects that are not supported for now).
https://github.com/E-Sh4rk/KururinTAS/tree/master/Misc
I have tested it on some levels (with Mohoc's bk2 files), it simulates perfectly the trajectory of the helirin even for wall clips and OOB collisions :)
There probably still are some inacurracies in some situations, but I will fix them as and when.
So now I can start the round 2: building the bot :P
It will surely not be able to compute an optimal path on its own.
However, when it is about finding a quick way to wall clip, it can't be worse than a human ;)
I will keep you informed!