Hudson had many classics in its NES library - Adventure Island, Faxanadu and Bomberman are just a few of the great titles it gave us all back then. Milon's Secret Castle probably shouldn't be counted among those.
As the title might reveal, you play as Milon, who has to make his way through a castle filled to the brim with secrets. In essence, it's a platformer, but it's a lot different from the standard issue where you just run right in every stage - every room of the castle has breakable walls that look no different from the rest, and most of your time will be spent aimlessly wandering around trying to uncover secrets, which are almost always necessary to advance.
The only way forward is to find a key, which can show up in any number of ways depending on the room. Mercifully, you only need to find keys the first time you play each room, so if you mess up somewhere and get sent back to the beginning of the game, you can just run through every room. Secret shops are also abundant in the castle and frequently have required items which you'll need to collect plenty of cash for, so be sure to look for them. They also offer hints, which most of the time, you will need.
Despite this kind of slow-paced gameplay of simply looking for hidden items and doorways, there are still enemies to deal with as well. For some reason, Milon's weapon of choice is to shoot bubbles, which as you might guess isn't very practical. As if that wasn't bad enough, he can only shoot them at an upward or downward angle, the default being upward - this means that very frequently, your attacks will simply fly straight over enemies and you'll need to get in very close to actually hit them. Milon also doesn't have that good old temporary invincibility after taking a hit like many other videogame heroes do and handles quite strangely, so it's not uncommon to be forced to take multiple hits if you get hit once.
If you do manage to make it past a number of rooms, you'll find out that this has bosses as well and practically all of them behave exactly the same, simply hopping back and forth while flinging projectiles your way. The only thing that changes between them is their health, and it quickly gets pretty ridiculous - if you don't find a certain strength powerup, you'll have to strike the final one no less than 64 times, while you die with less than 10 hits if you haven't found any health extensions. Better find those items!
The game's graphics and music haven't aged very well, with the castle having very basic-looking, repetitive rooms, and similarly repetitive music, with it only really changing up in the underground or during bosses.
Milon's Secret Castle might be a name you've heard mentioned occasionally, but believe us when we say it's probably not because of any good reasons. Unless you're a glutton for punishment, we recommend playing the game's sequel instead - it stars the same character but completely does away with all the tedious gameplay in order to be more of a simple, cute platformer.