Here is the full list of all 21 El Paso, Elsewhere achievements.
Kill a mega enemy.
Heal 50 times.
Kill the Puppeteer for the first time.
Hit 1,000 weak points.
Save 10 hostages.
Clear the first Landmark level.
Clear the tutorial.
Find all Pill Cop segments.
Find all projectors.
Defeat Draculae.
Defeat Djedefre.
Get the "Scars Fade" ending.
Get the "Thanks for Believing" ending.
Collect the Uzi.
Collect the Launcher.
Stake 250 enemies.
Roll 150 times.
Dive 150 times.
Kill 5 hostages.
Kill the Burned Man.
Kill the Angel.