Persist, and you will be rewarded
What are the difficulty stages in a game? Easy-Medium-Hard-WTF. Except there is no Easy in Dragonfire. The game throws challenges at you right from the get-go, until you reach the final campaign scenario -Slaadi Plague- which is laugh-out-loud hard.
Dragonfire is a reimplementation of Shadowrun: Crossfire in a Dungeons & Dragons setting. Even though the game comes with a campaign booklet that provides a storyline to follow as you progress the missions, it's not exactly dripping with theme. The cards are very well-illustrated, though, (images taken from older D&D material, if I'm not mistaken), so at least you will be looking at good artwork while you play.
If you browse the threads on the game's BGG page you will see a lot of complaining. Some of the complaints are justified and some are by people who just don't like to lose. Having played through the base game (currently stuck at the final scenario), I can tell you this: if you enjoy card games and combos, and don't mind repeating missions, chances are you will enjoy Dragonfire. I have enjoyed it a lot.
In case you are interested, here are some tips:
1. Skip the tutorial mission of the rulebook and start straight with the first scenario of the campaign (Dungeon Crawl). Unlike other tutorials that give you an easy-peasy glimpse of what is to follow, this one instead teaches you how to lose. You don't need that, as it will only make you begin the game sour and frustrated.
2. Read the rulebook, but make sure you watch the gameplay video by slickerdips as well. The rulebook is not well-written and may lead to confusion and mistakes (it happened to me). If you combine it with the video, however, you will understand everything and jump right in.
3. Almost everyone recommends that you play the game with 4 characters. If you can do that, good for you, as this was the way the designers originally intended it to be played. I tried it but the upkeep was too much for me, so I resorted to playing with just two. I have made it up to the final scenario, so I can assure you it's doable. Managing 2 heroes has the added advantage that they will collect enough money to buy powerful cards from the market.
4. Do not purchase this game if the idea of losing a lot in order to gain XP and level up doesn't appeal to you. This is exactly what happens here. You start off inexperienced but, with every loss, you gain experience points. When you gather some, you exchange them for stickers (or written notes for me, I hate stickers). The characters gain abilities and become a little bit stronger. Leveling up is slow: it will take effort to build up. Thankfully, missions are short and set up is fast. After each loss, you can easily start over.
Even though Dragonfire is listed as a deck building game, you do not get to thin your deck. You just buy cards from the market, and add them to your hand - not your discard pile. Coordination between heroes is crucial, and taking out enemies is very satisfying. Luck plays a part as well: the market gets refreshed often, but it may not have the right cards at the right time. Some enemies are more manageable than others, some Dragonfire cards (nasty event cards) are not as bad as others. Luck of the draw is ever-present.
If you know what to expect from the game, I believe you won't be disappointed. I am a fan of deck building and card-driven gameplay, and don't mind repeating missions, as long as the game is fun and winnable. For others, it may feel like too much grinding. I'd say check out the video by slickerdips and dip into it if you feel up to the task.