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.
Land a 1,000,000+ point combo.
Find every alien plushie.
Place 500 objects in CAP.
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.
Spend $10,000 in the Skate Shop.
Earn the "Veteran" Challenge Collection.
Give 50 Letters in Horse.
Paint 100 surfaces in Graffiti across all playtime.
Complete a match in multiplayer.
Complete every goal in THPS1 Classic and gain all gold medals.
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.
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.
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.
Achieve a High Score of 1,000,000+ on any classic Park.
Unlock School II in THPS2 Classic.
Earn the "Rookie " Challenge Collection.
Unlock Roswell in THPS1 Classic.
Create a skater using the CAS system.
Bail a 100,000+ point combo.
Earn a Medal on any competition park in Tours.
Achieve a judge score of 99.9 on a competition run.
Reach Career level 10.
Break 20 Panes of Glass.
Land a 50,000+ point combo.
Unlock School in THPS1 Classic.