I did not write either of those games.
Soft Pixel Dungeon is not as hard:
- You can optionally load and save your games
- You can optionally make the game not so hard with useful stuff dropped in long grass and larger search radius.
If you choose not to use these options then the game is identical to Shattered Pixel Dungeon.
NOTE: When you die you have start start a new game, then go into settings while playing the game and load up a previous save.
There is no auto-save so you have to go into settings to save or load your current game.
Load and save games for each class individually (you can not load up a Mage game while playing as a Warrior) .