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