Here is the full list of all 24 Pressure Overdrive achievements.
Didn't touch the ground for 15 seconds.
Defeated 1000 enemies.
Defeated 100 enemies through ramming.
Got in love touch with 10 enemies.
Defeated 5 enemies with one strike.
Finished a level without taking any damage.
Brought 5 love-touched enemies to the finish line.
Had a Spatank drag the buggy with a grappling hook for 30 seconds.
Defeated 18 enemies while a powerup was active.
Finished 20 levels in Endless mode.
Finish a level without driving on 'low pressure'.
Finished 10 Hornets with the railgun without missing once.
Finished a level with the buggy at maxed-out hull.
Finished a level with a buggy at maxed-out pressure capacity.
Finished a level with a fully upgraded Teslagun and Tesla secondary.
Finished a level with having activated underbody or rear explosives for 20 times.
Let a Sucker suck at least 10 pressure pills before destroying it.
Defeated all enemies in a level (Tutorial excluded).
Defeat the Riverbed Boss in Level 11.
Defeated the Castle Boss in Level 22.
Defeated the Underground Boss in Level 33.
Finished the campaign on Easy difficulty.
Finished the campaign on Normal difficulty.
Finished the campaign on Hard difficulty.