What an impressive game! I was looking into non-euclidean geometry games and stumbled upon yours, really cool take!

I had some issues installing it on Arch (easy to fix but some may find it helpful). This is how I finally made it:

$ pacman -S sdl sdl-ttf sld-gfx
# maybe also the sdl2 counterparts but I had them already (dunno)
# and maybe
$ pacman -S sdl_mixer

After that, if, even with the SDL libraries installed, make outputs something like

In file included from sysconfig.h:348, from hyper.h:19, from hyper.cpp:23:
/usr/include/SDL/SDL_gfxPrimitives.h:38:10: fatal error: SDL.h: No such file or directory
    38 | #include <SDL.h>
       |          ^~~~~~~
compilation terminated.
make: *** [Makefile:144: hyper.o] Error 1

change the line 45 of the Makefile to:

CXXFLAGS_EARLY += -DLINUX -I/usr/include/SDL

Finally, once running the game (execute the generated compiled file), if you receive an error like

error: Font file not found: DejaVuSans-Bold.ttf

put a DejaVu Sans Bold file in the root directory of the game (for instance, from here).

Now, run the executable and you're ready to go.