(Because the download is an exe from mediafire, I've mirrored this game here.)
Dragons! is a very simple and minimal dungeon crawler. Guroo's suggestion that it's about 5 hours long seems accurate, but it doesn't actually have that much content. The plot is virtually nonexistent, consisting of just a few textboxes. Starting with a party of 4 generic heroes summoned by the king you find there there's no town to explore, just an inn and shop (and you have no gold), so there's nothing to do but walk straight into the first dungeon.
Before getting deeper into this game I'll mention the best part of it by a nautical mile: the completely original and excellent 10 track soundtrack. It's relaxing and doesn't become irritating after a long time. I think it's heavily influenced by some songs I've heard in other games, but I can't pinpoint them. You can listen to it and other tracks on Guroo's soundcloud account. However, there are no sound effects, which I find makes things more boring.
Unfortunately the music has been unnecessarily encoded into ogg files at the maximum quality setting (500kbps) which means the game is so large that it greatly exceeds SlimeSalad's maximum download size.
The graphics and maps in this game are almost as minimal as the plot. Most dungeon segments are made out of just 2-3 distinct tiles and make uninspired use of them, though they are large and somewhat non-linear, requiring a little exploring. There are only a few NPCs/savepoints or items to find. This seems excessively lazy, considering that quite interesting maps can be made out of a few base tiles; just look at Dragon Bustier or Star Quest.
Each dungeon does however feature its own music and small selection of enemy types, and there are frequent miniboss battles. Battles are turn-based and can't be run away from. Thankfully the encounter rate is pretty low, and grinding and backtracking are unnecessary. The game seems to be decently balanced and playtested, with levelups reviving and restoring all heroes to full HP/MP just as you need them. That's the good news.
Bad news: Battles in the early game aren't much more than spacebar mashers, with no utility items aside from HP/MP potions which are quite expensive, and no initial skills beyond the cleric's heal and mage's force bolt. Each hero learns a new skill every 5 levels, but they don't seem to add much, being only buffs and more powerful attacks. For example the lvl 5 Warrior skill is just his standard attack with 20% extra damage! That's not an interesting decision for the player. There are no elemental attacks and I couldn't see much strategy beyond "kill the hardest hitting enemy first". For a game which is nothing by battles, this is a very serious problem. I suggest looking at Dragon Bustier for how to create a fun minimal dungeon crawler. However, Dragons! doesn't have lots of backtracking/grinding which is one improvement over Dragon Bustier.
I did find enough interest in the battles (especially minibosses) and exploration to keep playing for a while. Unfortunately I charged straight back in to the first dungeon after beating the initial segment, neglecting to save or buy anything, and ended up doomed when my cleric died most of the way through the dungeon. I had a look through the later game in Custom, and am very surprised that there are two more heroes that join, allowing you to customise your party. Actual choices like that need to be presented earlier and throughout the game, and especially in the battles.