I started playing Hustle Castle some time ago and couldn't have been happier at the time when I first started because everything was so similar to Fallout Shelter. Hustle Castle really had a similar vibe right off the bat, but I did enjoy the different style of combat which gave me more of a "tactical" feeling about the game that I didn't get from Fallout Shelter.
At first, I thought Hustle Castle had a better combat system... but as I've played more and more, I've slowly realized that it just doesn't hold up that well. The combat slowly turns into more and more of "who has the better items of the single best strategy" sort of thing. In a perfect world, without a way to outplay an opponent with skill, there needs to be a way to counter each strategy... but that just isn't the case with this game. Quite simply, if you try to do more fun things and change up your build, you'll just lose to whatever the strongest strategy is, which is usually some sort of silly continuously resurrecting some really powerful tanks. The only way I've found to reliably counter strategies is to just be stronger than your opponent and/or have better items.
There is a little bit more which can be done with the combat in Hustle Castle which MAY be able to sway thing in your favour by upgrading spells and bringing them into combat with you. There is a selection of spells including one to damage a random enemy, one to heal your most damaged character, and one to increase the damage of all your troops for a few seconds. These spells can be very powerful when used properly, though I still tend to find that the combat relies much more on how powerful your units are rather than any sort of strategy involved.
Of course any time you leave the game for a while and then come back to it you'll get a lovely update on any attacks which have been done against your castle and the result of them whether it was a win or a loss and you can even watch the combat replay if you want to see exactly how the fight went.
All of these combats are found through the world map which allows the player to continue along the "campaign" trail with each area unlocked having a selection of opponents who can be battled whenever you wish. Once you defeat another player on the map one time, their castle will disappear and be replaced some time later with a new one from another player. After some time, an option will appear which will allow an opponent to be "re-rolled" with another player who may be at a higher/lower/equal level.
Besides the campaign and battling other players there are a couple other options available to keep you busy in the game including a portal which opens up every once in a while which gives increasingly difficult levels of battles that can be done to gain more soul shards which can then be traded in for rewards such as epic items and resources. I have personally found the portal to be quite fun while it's open and then the game slows down a lot with not as much to do while it is closed.
If not busy doing portal fights there is an arena system which lets you put your best combinations of troops up against those of other players in a tournament-style system where you earn more points depending on who you choose to fight and win against. So far I have only managed to be in tournaments where I can perform reasonably average, but I've never been able to win because there's always another few players who have really powerful combinations of units or who are at a much higher level.
Winning one of these tournaments rewards the player with a chest which would have....... I'm not really sure, seeing as I've never won, but I assume there are some pretty good rewards in these things. However, competing in these tournaments does provide another type of resource which can be traded in for more epic and unique items.
Speaking of chests, there are a bunch of different chests which can be earned in Hustle Castle which have varying types of rewards inside of them including resources and items which can them be used to equip your characters whether that is for fighting or for making more resources faster.
Opening chests is also a very simple and kind of fun process of hitting the next open button which continues to open more chests as long as you have another chest to open. I don't know what it is about opening chests of random rewards that's so much fun even when 90% of them don't have anything useful in them.
Moving away from the combat system, there is some castle management which needs to be done while you're not out fighting monsters or other players. In this game, that comes down to building what rooms are available and upgrading them whenever possible. The castle rooms produce resources as time goes on which can be used to construct more rooms or upgrade existing ones depending on what is available at your current player level. One one hand, this is nice because there is a clear build path, but on the other hand I don't like it because there's no customization or learning curve to it besides "I better make this because it's available to me." Definitely ups and down on the castle management depending on how much customization and learning you like in your games.
My personal thoughts on Hustle Castle are quite mixed. I really like how well made the game is and how fluid the combat system is as well as the simplicity of the castle management. As far as a long-term game goes... this one falls flat just like all the other idle-simulation type games out there. Once you get far enough into the game you start having to save up so much resources that the player loses interest in waiting before being able to do things again. There's a great start to this game which really gets you into it, but with the usual idle-roadblocks I found myself losing interest. Granted, usually I lose interest because the wait is too long and there isn't really anything to progress to after a while... only this time my loss of interest wasn't because I didn't have anything to progress to; I lost interest because I hit a wall where the only solution was either to spend real money, or to wait days or weeks before being able to upgrade enough to make any real progress.
Summary
Gameplay: Being the most important part of a GAME, I thought the actual gameplay was quite fun right off the bat up until I wasn't able to progress any further without waiting for really long times due to needing resources and upgrades and training times before being strong enough to get past certain areas and boss fights.
Sound: There's not much of note to the sound design to this game. All the noises fit well without being annoying and the music is nice to listen to, but playing the game without any sound doesn't really make any difference to the enjoyability especially when only logging in momentarity to collect resources and then turn off the game.
Replayability: As the game went on, my interest in continuing to open the game went down and down with the increased upgrade and resource colletion times.
Bonus: If you enjoyed Fallout Shelter, this game has some similar aspects which will feel familiar and fun.
SCORE: I'm giving Hustle Castle 7.5/10. It's better than many other idle-type games out there with having more to do and being more interactive. The biggest downside for me is that it continues to suffer from the same problem as all the others where wait times get way too long without spending real money which I feel with this type of game would just go to waste.