I've been having a lot of fun with this for over a week now. Think vampire survivors tower defence. The mobile version is great on tablet, not so sure about on a phone though due to all the swiping in the early game. Although it has IAP I wouldn't call them necessary to keep making progress at all. I'm hoping more heroes and more complexity will be added in future as I feel like I'm approaching the end game already. It could also benefit from more in depth stats at the end of levels as currently it only shows you who is doing the most damage at the end of individual waves and that's not the best indicator of overall usefulness. Stats like overall damage for the whole run, total damage by type and for heroes things like being able to see the total crit chance (not just what has been added on by upgrades) would add another layer of depth to a game that already has more depth than I expected. Hope they keep working on and improving this!