In the Bedroom in 2007, you should unpack a green baseball hat. You can place it in the Bedroom to complete unpacking; however, take it into the Dining Room and move the camera up to notice a Mannequin Head. Place the baseball cap on the mannequin head.
Below is a full walkthrough of every missable achievement in the game with timestamps and English commentary!
Timestamps:
0:00 - Intro
0:17 - Solve A Puzzle Achievement (1997)
0:30 - Blast Some Tunes Achievement (1997)
1:00 - A Sometimes Food Achievement (2004)
1:35 - Electrical Hazard Achievement (2004)
1:58 - Strike A Pose Achievement (2004)
2:22 - Gotta Flush Em All Achievement 1/7 (2004)
2:32 - Game On Achievement (2007)
3:03 - Hat On Head Achievement (2007)3:47 - Gotta Flush Em All Achievement 2/7 (2007)
3:53 - Tidy Whities Achievement (2010)
4:45 - Brew Some Coffee Achievement (2010)
5:55 - Gotta Flush Em All Achievement 3/7 (2010)
6:01 - Rediscover Childhood Achievement (2012)
6:30 - Brilliantly Solved Achievement (2013)
7:20 - 12 : 00 Achievement (2013)
7:57 - Gotta Flush Em All Achievement 4/7 (2013)
8:04 - Gotta Flush Em All Achievement 5/7 (2015)
8:11 - Fuzzy Friends & Baby Builder Achievements (2018)
9:21 - Gotta Flush Em All Achievement 6 & 7/7 (2018)