If you approach this game a VALUE perspective, it's hard to beat. $3 for a truly absurd amount of content and replayability is amazing.

That being said, it becomes more shallow over time as the difficulty curve actually works downwards as you power up your characters. After 100 hours I could practically AFK and make it through 30 minutes of survival.

It's a fun distraction if you need to turn your brain off for a while and it absolutely nails the visual spectacle of mowing down hoards of creative enemies. It's not a whole lot more beyond that, but it doesn't necessarily need to be.