Be bad guys, stop heroes, save the gold
The premise is that you choose a dungeon master (1 at first, 2 unlock in the base game) and then a dungeon to defend. This dungeon comes with a set of monsters, traps, and a relic (usually). You go through weeks getting chances to improve assets until its time for heroes to invade. Position your monsters and traps, then execute the battles to stop them. There is a demo available, so check that out first if you're unsure.
The Good
-Fans of games like Iratus LotD will likely have some fun here. There are quite a few monsters, each with some unique abilities, and the relics give interesting power-ups that can help a lot.
-Heroes can be beaten either through physical damage or mental giving options for your setups
-Masters are unique, each having a special gimmick room once you progress far enough (one has a mid-boss monster for instance)
-Gameplay is fast, you can finish a dungeon in as little as 30 minutes or less once you know what you're doing, and the ability to keep moving helps hold interest
-Tough challenges for those who want them, Ascension and Endless modes add continual penalties to increase difficulty and push the player
-Nice visuals and sounds
The Bad
-Those who dislike RNG will have a lot of problems, you control your dungeon setup, but not the order of rooms, so you might have a great strategy that you can't use because the rooms are out of order for it; RNG also determines the heroes and sometimes that means you get a group that happens to be perfectly setup against your tactics meaning it may be unwinnable
-The game can be short if you have no interest in Ascension/Endless (although each master still has about 7 dungeons to play as of this date)
-Chances to gain new assets are also RNG, so you may not get one that fits your tactics when you really need it
The Bottomline
If you can handle RNG and accept its outcomes, you'll likely have fun here. It's funny at times and fun to play. Try the demo and see if it suits you.