Behind the scenes
It's a real program, not a screen recording of me typing:
gcc main.c -o intro -lncursesw -lm && ./introWith asciinema, agg and VT323, on a dark screen:
TERM=xterm-256color asciinema rec --cols 67 --rows 17 -c "timeout --foreground 28.60 ./intro" raw.cast
# keep one loop, drop the exit
jq -c 'select(type == "object" or (.[0] < 27.97 and .[1] == "o"))' raw.cast > demo.cast
agg --renderer fontdue --font-dir fonts --font-family VT323 --font-size 40 --line-height 1 --fps-cap 30 --last-frame-duration 0 \
--theme 111111,c5c8c6,282a2e,cc6666,b5bd68,f0c674,81a2be,b294bb,8abeb7,c5c8c6,969896,cc6666,b5bd68,f0c674,81a2be,b294bb,8abeb7,ffffff \
demo.cast raw.gif
# CRT look: monochrome, glow, scanlines, curvature, vignette
ffmpeg -i raw.gif -filter_complex_script crt.ffscript -fps_mode passthrough -loop 0 demo.gif