The hunt is over! Thanks so much for solving! Solutions are available for all puzzles. A wrap-up post will be coming in around a week late January.

The Holzers

Solves

Total: 20

Toggle spoiler tags for secret content:
Puzzle Solve Time
10 Flipping Channels
20 Go Fish
21 Magic Is in the Air
14 Ice Pack
17 Sack of Gifts
19 Those Crafty Penguins
16 Tidying Up
15 Migratory Birds
13 The Arcade
12 High-Rise
11 Check It Out!
9 Overt Infiltration
6 September of the Puffins
7 Spy Games
8 Survival Stories
5 1. e4 e5
4 Subnivean Snake
1 Penguin Pidgin
3 Double-Crossed
2 Metrology Lab