This achievement can only be achieved in Night Run mode
This achievement can be tricky if you decide to do this at the start of the run. If you chose to try to get it at the start of your run, then navigate the first level
without activating your flare. Once the the ending is in sight, activate your flare.
You now need to carry this flare through the next 4-5 levels without it dying.
If you decide to do this late in the run, focus upgrades towards once that give better efficiency and make it brighter.
The more efficient the flare is, the longer it last, and the easier the achievement will become.