I'll start with tips which you can beat the game with some luck.
MAKE EXPLOSIVE BOMBS, this will help you clear most levels and easily clear bosses. Literally buy as much saltpeter as possible.
Try to clear a level with as little damage as you can, if you can clear a level without using bombs or taking damage, just do it. Skip everything you can.

If you save and quit the dungeon, you will get a new version of the dungeon when you resume it.
This means being able to reload levels where you know you will have to take mass health damage so you get a better roll of mobs (like a bunch of scarabs).
It means being able to collect food and reload for more if your almost out.
MOST IMPORTANTLY, it means being able to reload trader areas which will reload your free gear item and sometimes the shop keeper will carry different items, in case you need saltpeter or hp. You can also get infinite free gear so you can always get your charge back to max (technically you can do this for infinite money but its too slow to really be worth considering).
You cant do this on blacksmith, potion or event levels. It will just skip you to the next level.

Using the save and quit trick you can get infinite armor.
Keep reloading and checking your free gear till you get the shield that gives you armor when you equip it.
After you equip it, every time you save and quit, it will give you the armor again when you resume. You can do this infinitely.