a batch change from ship to self broke the thing that kept the player on
the screen. also spawn_goodie got missed in the migration to `_ENV` for
looking up stuff by name.
Vacuum Gambit is about to stop being a Tyrian clone. The hybrid of
Mega Man Battle Network and Slay the Spire mechanics lends itself better
to Galaga than Tyrian. updatedshmup.p8 remains an excellent basis for a
Tyrian-like shmup, especially since it has a (demo of a) level loading
engine that reads strings, and maybe I'll even implement something along
those lines someday -- but I'm about to tear it all down to build it up
again, starting with the entire model for levels and progress, followed
shortly by the "energy" system and its interaction with shields.
(long-term plan: shields will auto-recover after every "flotilla", but
health will be more difficult to recover. Player shots will be limited
entirely by ammo and cooldown, replacing the "burst throughput" vs.
"sustain throughput" system created by the generator, although some
enemy firing patterns may recreate that behavior.)
(plan for the "level" system: create Galaga-style flotillas. I think
ship behaviors can reasonably be declared in the 8 bits available in
sprite flags, meaning I can program simple enemies entirely from the
sprite sheet and draw flotillas on the map.)
