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