Hitman: Blood Money

Each tier of the Kruger Schmidt upgrade shop is unlocked while playing through the game normally. To recieve the achievement, you have to have every upgrade purchased and then complete a level.

The upgrades are as follows:

Tier 1 - $50,000/each

Low Velocity Ammo
Silencer Type 1

Tier 2 - $75,000/each

Extra Ammo
Laser Sight
Rail Mount

Tier 3 - $100,000/each

Magnum Ammo
Longslide
Dual Action

Tier 4 - $150,000/each

Red Dot Sight (Requires Rail Mount)
Larger Clip

Tier 5 - $200,000/each

Silencer Type 2
Scope Type 1 (Requires Rail Mount)
Full Auto Fire (Requires Larger Clip)

To unlock this achievement, you must purchase all upgrades for the Silverballer.
You won't be able to buy the latest upgrades until the "Till Death Do Us Part" mission. The total cost of all upgrades is $1,325,000.