Here is the full list of all 36 Tony Hawk's Pro Skater 1 + 2 achievements worth 1,000 gamerscore.
Earn 2,000,000 points in Combo Mambo across all playtime.
Give 50 Letters in Horse.
Find every alien plushie.
Earn 5,000,000 points in Trick Attack across all playtime.
Spend $10,000 in the Skate Shop.
Get hit by a vehicle on every map that features them.
Find all Stat points for any Pro Skater.
Achieve a High Score of 10,000,000+ on any classic Park.
Land a 1,000,000+ point combo.
Achieve a High Score of 1,000,000+ on any classic Park.
Get hit by the Bull in Bullring.
Place 500 objects in CAP.
Bail a 100,000+ point combo.
Unlock Roswell in THPS1 Classic.
Unlock Bullring in THPS2 Classic.
Earn any 4 Medals on competition parks in Tours.
Paint 100 surfaces in Graffiti across all playtime.
Complete a match in multiplayer.
Earn the "Rookie" Challenge Collection.
Create a new park and upload it.
Land a 50,000+ point combo.
Earn a Medal on any competition park in Tours.
Reach Career level 10.
Unlock School II in THPS2 Classic.
Break 20 Panes of Glass.
Unlock School in THPS1 Classic.
Create a skater using the CAS system.
Complete every goal in THPS1 Classic and gain all gold medals.
Complete every goal in THPS2 Classic and gain all gold medals.
Unlock Officer Dick.
Earn the "Veteran" Challenge Collection.
Earn the "Legend" Challenge Collection.
Complete all "Hard" Get-Theres.
Reach Career level 100.
Complete all Gap collections.
Achieve a judge score of 99.9 on a competition run.