What makes this game good:
- Features some amazing corruption and body modification/transformation scenes from GFF (so if you know his previous work or like games with the featured tags then you may get some enjoyment out of it)
- Features different routes once you defeat the final boss and provides some enjoyable sex scenes
What makes this game bad (in my opinion):
- Slow and tiresome grind, with each enemy killed only managing to give you a small amount of xp and currency (and the occasional loot); so in order to be able to fight off some harder enemies in the more difficult levels you have to spend a large amount of time fighting off monsters in the current level (also worth mentioning that the xp cap increases with each level, only adding more to the bothersome grind)
- Enemies spawning in at random can make the game infuriating at times instead of fun, especially when you just want to progress to the next level
- Maps are rather large and don't offer much for exploring said maps (asides from a sex scene in that level and rewards for opening chests), discouraging the player from exploring too much
Conclusion:
Princess of the Horny Monster provides some great sex scenes, especially for those who are into corruption and body modification/transformation. However I don't think it's worth playing the game in order to enjoy said scenes (unless you want to grind); you're better off just looking at them in a folder instead of grinding to get the scenes you want.