Thanks for playing and for the nice comments! It is a bit on the tough side and could use some more balancing, that's for sure. And yes, it is done in assembly and runs on a stock Commodore 64 or any new hardware or emulator. It's a passion.
I use an IDE called CBM Prg Studio, a text editor and an assembler that builds executables for C64, plus some built in editors for graphics (though I mainly use external editors, own or 3rd party). Many use an assembler called Kick Assembler and VS Code with 6502 extensions.
