Wasteland 3

Just die during the first combat.
Move your duo out of cover, dont ever attack the enemies, especially with the vehicle and keep ending your turn (Hold B). You can try on the hardest difficulty to speed up the process with a new game.

Alternatively, if you want to continue your save and not to start a new game, you can always die in the next fights but before leaving the ambush site area/tutorial area.

No-Show
You never made it to Colorado Springs.

This is a easy achievement, however you can miss it. In order to unlock the achievement you must fail to make it to Colorado Springs. The fastest way to do this is to let all of you units die in the first battle. To make this faster play on the hardest difficulty, then send you units out into the open & keep ending your turn. To end your turn press & hold . Make sure you do not use the armored truck's attack. For anyone that would like a video guide I made one as well.

Die during prologue (Ambush Site)

I was already past this point, but still had a save and blew the party up with grenades found during the prologue. Or use oil tanks or just restart the game.