Played this for 2 hours. Didn't get it at first, but when I did I found it had more strategic and tactical depth than I expected, and it kept me fixated on figuring out better strategies. Didn't survive floor 3 at first, but eventually got to floor 11.
The premise is simple. You fight 4 yetis on each level. You must fight them in order and backtracking can cause your sanity to deplete, so there is some tactical thinking about pathing. Each yeti you face has the displayed life. When you attack a yeti, first your sword damage is applied, then if you have any arrows the bow damage is applied (and you lose 1 arrow), then if you have enough magic given spell cost, the spell damage is applied (and magic score reduced by spell cost). If the yeti still has health after all that, it damages you according to its power. The combat cycle then repeats until one of you is dead. I am not sure how the numbers change are obvious, it took me a while looking at how they changed during combat to figure out exactly what was happening.
Picking up different items on the tiles increases your stats - sword damage, bow damage, spell damage. It is crucial to surviving later levels to keep these stats heading upwards as the yetis become more powerful as you go. However it isn't as simple as hoovering up every item on the level.
Certain items are more important than others, and some items seem to become more or less important as the game progresses. To give one example of this, I suspect it might not be wise to pick up too many of the spell stat increasing staffs up, as counterintuitive as that is, as while spell damage goes up, spell cost also goes up at the same time and eventually being able to cast becomes a rarer event - so instead of being able to inflict moderate spell damage against each yeti you fight on the level you find yourself in a situation where you can only inflict immense damage against one of them and have no magic left for the rest. And if you can only do 80 sword damage and 100 bow damage, but the yeti has 181 life and 200 power, then you are about to take a 200 health hit, all for the lack of being able to do a single point of spell damage. Also in the later levels when the yetis get this powerful you want to kill them before they can strike you. I found there weren't enough health items on the level to be able to engage in many multi rounds of combat as in early levels, at least with how I was playing. All in all a good game.