Neat little game. I've taken to setting myself challenges for each run to add more variety, such as:
-Pyromania: Don't use any items that reduce heat; no ice cream, snowmen, hot flames, etc.
-One Hit Wonder: Don't use any max health upgrades.
-Respect for the Dead/ Actual Archaeology/ Five Second Rule: Don't loot any corpses/ Don't open any chests/ Don't pick up anything from the floor of the rooms.
-Not One Step Back: Never backtrack unless you've hit a dead end.
-Picky Earner: Only pick up stacks of coins that match your current floor, e.g. only pick up single coins on floor one, only pick up stacks of 6 on floor six.
I find it adds a lot of replayability and difficulty. Perhaps a future version of the game could implement an achievement system?