Once you have a successful run you can get all the achievements rapidly. This is what worked for me:
1. Penny Slinger
2. Diamond
3. Iron Shield
Each fully upgraded by the end.
Then you need to pick up vampirism, mirror and respin along the way.
Upgrade the penny, to a coin bag, to a diamond, but dont get rid of the coin bag until you've levelled up the diamond. Make sure you upgrade from a regular shield to the iron shield because if you don't the final boss might be able to kill you.
The only upgrades you need are the extra slots.