Shmup
Nine waves and a boss, or an endless mode that deals you one of three upgrades a level — both fitted inside PICO-8's token limit.

What the limit did
PICO-8 is Lua on a fantasy console with a hard cap on tokens. Everything has to earn its place — a whole shmup with two modes, fitted inside it.
That cap turned out to be the useful part of the project. Optimising for length *and* speed at once is a different way to write a game than writing it large and trimming afterwards, and it is the thing I would carry into the next one.
Two ways to play
**Wave** is nine scripted waves and a boss. There is a game you can finish.
**Arcade** is the other one. Enemies spawn wherever they like, you earn XP for kills, and every level deals you a choice of three cards to upgrade the ship. There is no win state — the waves are scripted up to level 18 and after that it stops holding your hand.
After
Hundreds of sessions. A streamer played it live. Also released on Lexaloffle.