Nyastrocat is my first program for the Astrocade (and also my first attempt at creating a program for a retro console): it plays back 7 frames of the Nyan Cat GIF while beeping the Nyan Cat tune.
I've tested this in MAME's emulation of Robby Roto, an Astrocade-based arcade machine; it should also run in MESS's emulation of the Astrocade as well as on real hardware.
I tried to RLE-encode all the images, however, my RLE decoding code fails on some frames of the Nyancat animation as well as on the NEO badge, so I've used text for the splash screen. Sigh.
Thanks to prguitarman for creating the original Poptart Kitty animation, and to Purufufuru for his transcription of the Nyancat song.