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