A lot of modern roguelikes (and I use that term in a very broad manner - once again screw the Berlin interpretation!) have nice graphics and easy-to-learn interfaces that make them accessible for more and more players - who then run against a wall of difficulty. Don't despair, in this series of posts I shall shine some light on those that I have played and beaten and give some tips regarding strategy and practice on each individual game.
Let's start this out with Pixel Dungeon. The game is made for Android-devices and is a classic random-generated, turn-based dungeon-crawl with an interface optimized for touch-screen use. It is also well-enough programmed to run on my old cellphone and doesn't mind a small screen. Plus you can zoom in and out and other nice touches. Pixel Dungeon is notoriously difficult and even the comments on the Play Store speak about how much is dependent on pure luck when playing this game. This is partially true but let me tell you what you CAN do to get ahead and beat this roguelike.
The game used to be, in fact, much harder than it is now. Back in the early days, when there were only four levels, later eight and twelve, you only had one generic type of character class and no nice things such as seeds and arcane styli to help you get by. So starting with a very early version of Pixel Dungeon has made the game get more and more easy for me. So has a lot of play-time on buses and trains - I have beaten the game with all four of the currently available classes. Which brings us to the first thing you need to consider: Your character class. For a beginner, I'd recommend to take the fighter or the mage, as both rogue and huntress are substantially weaker and require more refined tactics. The goal should be to beat the second boss, as that gives you the book for all future runs, allowing for further buffing and specializing for your character of that class.
Regardless of your class, know the following things: Whenever there is a room with piranhas, there will be a potion of invisibility on the level. Whenever there is a room with a treasure behind a grid of traps or a chasm, there will be a potion of levitation on the level. Whenever there is a wooden barricade blocking a treasure room, there will be a potion of liquid flame on the level. So, only try out unknown potions after you have fully explored a level and use your head. Being on fire is not deadly when you're in water. Figure it out. This is important as you want to always gather ALL treasure. Before reaching the first boss, the slime, you have ideally identified potions of strength, liquid flame, and healing, as well as scrolls of identify and upgrade.
Do not waste your scrolls of upgrade. When your goal is to beat the second boss, you may upgrade armors like the chain armor and above and weapons like the spear/quarterstaff and above if you believe that you will have the combination of strength and upgrade to wield them without being slowed down by the time you're on level 10. Do not upgrade anything you're going to discard later and upgrade weaponry before upgrading armor - you can wear armor when it's too heavy but a weapon that is above your grade is pretty much useless. Both warrior and wizard can reforge their starting special-weapons, so you can read any scroll and if it's an upgrade, it's not wasted.
Keep seeds of earth root, fire bloom and those green healing-seeds. Those are valuable to you. When you need to heal in-between fights, a green seed can replace a health potion. For bosses 1, 3, and 4, earth roots are immensely useful. Fire blooms help with boss 1 and 4, and allow you to cook mystery meat. This is valuable, believe me, but only do so once you have found more than one mystery meat and if there is other flammable stuff around so you can actually cook it all.
When you meet the ghost, always get its armor if you haven't found a decent one yet - you may get lucky. If you have found an armor, try a better weapon. If you need to battle the fetid rat, use ranged attacks and then try to engage it diagonally, as the gas it emits spreads in four directions, not eight. Attack, retreat, repeat.
The Goo, the first boss of the game, is very much beatable if you meet three conditions: You have a fire bloom seed, you have an earth root seed, and there is water next to the door leading into its chamber. Stand on the water before the entrance and plant your earth root under your feet. Walk into the doorway and plant your fire bloom seed. Get the attention of the Goo WITHOUT moving. When it reaches you, take a step back. You walk onto the earth root and into the water, giving you a massive armor-boost and protecting you from the Goos acid-effect, while the Goo moves onto the fire bloom in the doorway, setting it on fire and giving the fire fuel to burn for a long time. Now simply beat away at the Goo and remember to not leave your protective spot. This gives you a very good fighting chance.
Buy potions of health from the trader, possibly potions of identify. The wizard is best with a staff of firebolt, should you find one that is the weapon you want to spend your potions of upgrade on, just be careful not to burn yourself. Grind flies, beat them in a large room for maximum swarm-expansion - the more flies there are, the higher the chance of health-potions dropping. Be wary of skeletons exploding.
Fighting the Tengu, boss #2, the warrior can use a potion of levitation in the later stages of the fight to fly over the spawning traps. The mage ideally has a nice upgraded staff of firebolt by this point and can battle the Tengu at a range but be careful about damage and, if available, use another earth root. The Tengu is not very strong for a boss monster, just very mobile so bring a few health-potions. Once you beat this thing, you get the book of learning for the class you're using and that is worth something for all future play-throughs. So join me again next time, when I'll get to the later-game of how to beat Pixel Dungeon!