As the description says this is unlocked by surviving until the 31st minute in the Gallo Tower level. If you start this in Endless Mode death doesn't appear and you will be able to get to the 31st minute with no problem which may unlock this. If you don't have access to that then the following is the method I used.
Set UpFirst of all you will need to unlock the Randomazzo:
I also used the Arcana IV: Awake card which is unlocked by getting Krochi to level 50.
Running Through The LevelMy approach was to do this with the Arcanas option enabled for the level and select the Arcana IV: Awake card before starting my run. This gives you +3 revivals.
After starting the run my main priority was to equip Clock Lancet and Laurel. Clock Lancet freezes enemies in a clockwise pattern and Laurel shields you from damage. You could also look for the Tiragisú item which can give you two more revives. I also made sure to get the Wings item for the extra move speed as the tower fills up with water that you need to stay ahead of. If the water hits you it takes Laurel charges and leaves you vulnerable to the reapers.
All you need to do then is ensure you have enough damage / healing to get to 30 minutes. This will vary for each player as we all have our preferred builds.
As soon as the clock ticks over 30 minutes all enemies will vanish and the reaper will start chasing you. Run north, always north. The idea is that the Clock Lancet will freeze the reapers (hopefully before they get to you) and the Laurel will protect you for a while if they do. If/when you die just revive and start running again. Because the tower is filling with water if you get killed you'll need the Wings item to get ahead of it again.
I found that the Clock Lancet worked so well that once I'd passed 31 minutes I'd have to stand and wait for up to another minute for the reapers to kill me. On this level you can just run south and it'll be over pretty quick.