It is part stradegy, part chance. I've played and created RPG's for decades. I love the Rogue-like genre' because it is different each play. Typically though, by game 300 one usually gets at least one win. If you haven't won in all those years, you need to change your method of play. These types of games can not be won on pure hack-n-slash alone. Although videos may help you, they only show how THAT scenerio worked out at that time. Another option is to try another version of PD ( hundreds exist ). Although Shattered is one of the best it is not at all the easiest. Try playing EASY PD for example. Get in a few wins and get your confidence up. Then try a harder PD/SPD.
I presently have ascended with 4 of 5 classes with the new SPD, but I've been at this game for years.