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