GLIBC version requirement too high for Ubuntu 18 x86_64

[crystalsolenoid]

My OS version: Ubuntu 18.04.6 LTS
My GLIBC version: 2.27

Bitsybox will not run (see below for error messages).

Does bitsybox really require GLIBC 2.33, or can that be bumped down to something a little older for the pre-built version?

My detective work below:
So I'm not quite Linux savvy enough to understand exactly what's going on here, but I downloaded bitsybox_LIN.zip from itch and am not able to run it.

When I try to run it:

> ./bitsybox
bash: ./bitsybox: No such file or directory

Despite it having executable permissions and existing:

> ls -l
total 2660
-rwxrwxr-x 1 usrname usrname  832328 Oct 10 17:47 bitsybox
drwxrwxr-x 2 usrname usrname    4096 Oct 10 14:44 games
-rwxr-xr-x 1 usrname usrname 1868896 Oct 10 17:47 libSDL2-2.0.so.0
-rw-rw-r-- 1 usrname usrname    5088 Oct 10 17:47 LICENSE.txt
-rw-rw-r-- 1 usrname usrname     769 Oct 10 17:47 MANUAL.txt

I read online somewhere to try this command to check dependencies, but I don't really know how to interpret it:

> ldd bitsybox 
./bitsybox: /lib/x86_64-linux-gnu/libm.so.6: version `GLIBC_2.29' not found (required by ./bitsybox)
./bitsybox: /lib/x86_64-linux-gnu/libc.so.6: version `GLIBC_2.33' not found (required by /home/usrname/bitsybox_LIN/./libSDL2-2.0.so.0)
./bitsybox: /lib/x86_64-linux-gnu/libc.so.6: version `GLIBC_2.32' not found (required by /home/usrname/bitsybox_LIN/./libSDL2-2.0.so.0)
./bitsybox: /lib/x86_64-linux-gnu/libm.so.6: version `GLIBC_2.29' not found (required by /home/usrname/bitsybox_LIN/./libSDL2-2.0.so.0)
	linux-vdso.so.1 (0x00007fff87936000)
	libSDL2-2.0.so.0 => /home/usrname/bitsybox_LIN/./libSDL2-2.0.so.0 (0x00007f4779cb5000)
	libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f477987f000)
	libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f477948e000)
	libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f477928a000)
	libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f477906b000)
	/usr/lib64/ld-linux-x86-64.so.2 => /lib64/ld-linux-x86-64.so.2 (0x00007f4779c5c000)

With some googling, it looks like I can just run libc.so.6 to check its version:

> /lib/x86_64-linux-gnu/libc.so.6 
GNU C Library (Ubuntu GLIBC 2.27-3ubuntu1.4) stable release version 2.27.

So I guess the problem is that I'm a couple versions behind? I made sure my computer was up to date, but it looks like since it's such a key library, it's not recommended to update to a new version of GLIBC without updating ubuntu to 20?

(So excited to have bitsybox exist, thank you!!!)