Vertical Drop Heroes HD

I found the best way to get this, despite being random chance on the amount of chests per level in each run, was to find the merchant in a level that sells a skill that allows you to start with 5 keys.

Once you have this skill, start a run with any character that has the skill to start with. Then aim for every chest you can find. It does have to be in one run, so keep that in mind. You will find other keys as you go, but starting with 5 is a big help.

Some levels have a lot of chests, some don't even have any. So that's where luck plays a part. Just keep at it, and eventually you will grab this achievement.

One last thing, you may struggle to advance in the game until you upgrade your starting health and attack. This can be done in the game hub with the Blacksmith in the top left and Apothecary in the top right. Every consecutive upgrade will cost more than the previous as well.