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