Add the five LD60 Circular Arcade games as VS2 games

games/ld60/README.md

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+# LD60 Circular Arcade
+
+## Credits
+
+**The ideas for all five games are by
+[@borisvanschooten](https://github.com/borisvanschooten).** Together they are
+the Ludum Dare 60 entry "Circular Arcade", originally published at
+<https://tmtg.nl/ludumdare/ld60/jgame.html?game=jgame-games/ld60/>.
+
+Spiral Tunnel, Catch the Robots, Rim Runner, Dodge 'Em and Defender, their
+levels, rules, enemies and the idea of playing an arcade game on a circle all
+come from that entry. What this folder adds is only the port to Ventilastation:
+the VS2 code, the generated art and sound, and the changes listed under "What
+changed from the prototypes" below.
+
+## The games
+
+Five small games for the disc. The original plays on a screen that is bent into
+a circle; here the same five levels are written with the VS2 API, so the bending
+is done by the display.
+
+All five share a design:
+
+- The world is 32 tiles of 8 pixels, so it is exactly one trip round the disc.
+  Tile row 0 is the rim and the rows count toward the centre, on a `TUNNEL`
+  layer, so the rows near the rim are big and the middle of the disc is where
+  the ground, or the rest of the tunnel, is too small to play on.
+- The camera turns with you. You are always at the top of the disc (x = 128),
+  except in Rim Runner, where you run on the rim at the bottom, so the picture
+  never leaves your end of the display.
+- Things near the middle of the disc are hard to read, so the games with a deep
+  level scroll inward with you and keep you toward the rim: Rim Runner keeps your
+  feet about eight LEDs from the rim (but never shows more than 4 pixels of
+  ground below the lowest floor), Spiral Tunnel flies a quarter of the way in, and
+  Catch the Robots no deeper than halfway. They follow you to the very end of the
+  level instead of stopping where the map runs out.
+- Everything is made once in `build()` and moved afterwards: tiles come from one
+  `bytearray` shared with the tilemap, sprites are fixed lists, and the walls get
+  their outline from an autotile pass at build time. (Spiral Tunnel's edges are
+  slanted tiles instead, like the prototype's, since the tunnel moves sideways as
+  it goes down.)
+- You are scored on the time you take to finish. Faster than your best saves a
+  new best (`vs2.saves`, under the name `best`).
+
+| Game | You... | Controls |
+|---|---|---|
+| Spiral Tunnel | dive down a tunnel that winds round the disc, bombing the UFOs that patrol it | arrows steer (left/right change your speed round the disc), A bombs |
+| Catch the Robots | run through a random maze, catching all 20 wall-hugging robots | arrows |
+| Rim Runner | run and jump round the inside of the rim, collecting eggs, landing on birds | left/right run, up or A jumps |
+| Dodge 'Em | drive a five-lane track, eating pills while red cars come the other way | up/down change lane (only at the gaps in the walls), right speeds up, left slows |
+| Defender | fly over a planet, shooting the aliens before they shoot you | arrows fly, A fires |
+
+## What changed from the prototypes
+
+- Controls are the controller's, not W A S D and L.
+- Rim Runner's platforms are four tiles above each other instead of five. A jump
+  rises about 4.6 tiles, so the originals could not be reached from below.
+- The tunnel and the maze are shorter, and the numbers (speeds, gravity) are
+  scaled from the prototype's 60 frames a second to the console's 33 ticks.
+- The prototype ends a level; here every game ends with its time and starts again
+  on A.
+
+## Art and sound
+
+Art is generated, not drawn by hand: run `python3 tools/ld60_assets/make_art.py`
+to rewrite every `images/tiles.png`, `images/sprites.png` and `menu.png`, and
+`python3 tools/ld60_assets/make_sounds.py` (needs ffmpeg) for the MP3s in
+`sounds/`. The font is the tutorial's `steel8x8.png`.