Thank you for taking my observations into account, @alexherbo2! The README is much better now, and the kcr play is of great help (very good idea indeed).
I really like this program. It seems we can now somehow script Kakoune the way I would like to do.
People are complaining about it’s being written in Crystal, but I don’t see it as a problem (specially if you can provide binaries in its releases). Quite the contrary: it opens up the opportunity to be much more flexible in which languages you use to script Kakoune. As noted by @scr, this is exactly the Kakoune and POSIX way of doing things. If you want an inclusive community, you must to be open to tools written in whatever language the author is more familiar with. Diversity is the key.
Regarding kcr play, it’s worthy of notice that it works only with Kakoune compiled from master and not with the last release, since the latter lacks the -method switch of the write command.