Pretty enjoyable, but I thought it was a bit too tedious & anti-climatic.
1) The map system. It is buggy and doesn't really tell you where you need to be. Buggy because I can explore the whole map(before game is complete), save, exit and then come back to find there are still black spots on my map, seeming to appear in specific locations. Doesn't really tell you need to be because the doors are still shown when already unlocked, aggravated by the fact that the keys are shown in a separate menu from the map.
2) Traveling is very tedious, especially with the map being rather unclear on where you need to go, not to mention you can't take certain shortcuts until you're quite far into the game. Water is also really annoying to traverse, but fortunately the player have no need go into them even for secrets and can freeze the water surface(which takes a bit longer, but worth the effort). I think this game should have the ability to use the savepoints as teleport zones to reduce the unnecessary travel time. Because of traveling and the unclear map, I ended up killing so many enemies and unintentionally becoming over-leveled to the point where my magic charge time is instant. Plus, I got really bored of hearing the exact same music for almost the entire game that I ended up turning it off and playing my own music.
3) Difficulty is way too low. I'm alright with the normal mooks being cannon fodder, but the bosses are anti-climatic. Its really easy to dodge their projectiles and deal lots of damage to them, and even if the screen gets filled up with turrets, they can be destroyed, never respawn and the boss doesn't summon minions unlike your previous Diamond Hollow series.
Sorry, I would say its a downgrade from Diamond Hollow 2, but on its own its still a decent casual game if a little tedious.