If you’d like to read the full, unfiltered disassembly ramblings that led to this conclusion, go here. The results are summarized below on how to get the perfect town in Animal Crossing (GameCube). The results were derived by stepping through the assembly on the NTSC version of the game, but I imagine similar results for other versions.

Requirements

  1. Overall garbage count must be less than 5, excluding the Garbage Dump area (garbage in that acre, but outside the designated garbage area does count). Once the count becomes 5 or more, you must clear the garbage to zero.
  2. All acres, including “exempt” ones (listed below), must not have weeds outnumbering flowers by 5 or more.
  3. Non-exempt acres must have between 9-16 trees (inclusive).
  4. You must score 17 or higher “perfect acre” points, as outlined below.

Perfect Acre Scoring

For each acre, including ones exempt from the strict checks above, the following evaluations are performed in this order (bailing out as soon as one condition is met):

  1. If the acre has any garbage on it, you receive no point.
  2. If weeds outnumber flowers by 3 or more, you receive no point.
  3. If the number of trees exceeds 14, you receive no point.
  4. If the number of trees is 11 or fewer, you receive one point for every two acres like this.
  5. If the number of trees is between 12-14, inclusive, you receive a full point.

Exempt Acres

  1. The Wishing Well
  2. The River Pool (Fishing Tourney Spot)
  3. Train Station
  4. Player Houses
  5. Museum

One caveat is that I believe the River Pool doesn’t have weeds grow there, so it sort of bypasses the rule that exempt acres must not have weed overgrowth.

So ultimately, you can have 17 fully perfect acres, or 34 nearly-perfect acres, or something in between, and you’ll achieve the perfect town. Maintain this for 15 days, and the golden axe is yours!