Unpack as:

  $ zstd -d bootloader.zst
  $ zstd -d vmlinux.zst
  $ zstd -d sdc.zst

Boot as:

  $ bski ./bootloader ./vmlinux root=/dev/sda simscsi=./sd simeth=eth0 init=/bin/bash PATH=/bin rw

In newly opened xterm window:

root@(none) / # source /etc/profile
(none) / # gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/ia64-unknown-linux-gnu/11.2.1/lto-wrapper
Target: ia64-unknown-linux-gnu
Configured with: /var/tmp/portage/sys-devel/gcc-11.2.1_p20220115/work/gcc-11-20220115/configure --host=ia64-unknown-linux-gnu --build=ia64-unknown-linux-gnu ...
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 11.2.1 20220115 (Gentoo 11.2.1_p20220115 p4) 

(none) / # echo 'int main(){}' > a.c
(none) / # gcc a.c -o a
(none) / # ./a
(none) / # file a
a: ELF 64-bit LSB pie executable, IA-64, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux-ia64.so.2, for GNU/Linux 3.2.18, not stripped