Super fun game! Played for a couple of hours yesterday and today. Joined the Discord and learned I actually beat the game (Behemoth's lair is the last level in case you're wondering). The dev is friendly and working on new updates, looking forward to coming back!
A few helpful tips:
1. Prioritize the mana upgrades in shop. They are permanent (this wasn't clear to me when I read the description), and make a huge difference.
2. Don't think too much about the non-legendary items, they'll be replaced sooner or later.
3. Pyromancer is OP, I got mine to 390 dmg. With barrier + 2 blocks item + Priest as support, this guy just melts everything and doesn't die. The barrier is super key because it prevents knockbacks while it's up. In comparison, berserker gets stunned or knocked back a lot more, which limits damage.
4. IMO, Priest is the best starting class, so I'd recommend trying a few runs to unlock Priest and start a run with Priest.
5. AOE dmg in the form of Berserker's whirlwind or item that has 4th strike is flamestrike (an AOE bomb) is great for clearing lanes. The AOE actually hits additional top and bottom lanes.