castle idler
Posted October 6, 2025. Updated November 3, 2025. Played 2050 times for a total of 1660 hours.
description
castle idler is a short, relaxing, wave-less idle tower defense game. idly upgrade towers, collect coins, and unlock a vast skill tree to defend your castle from a slime invasion.
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deploy a variety of towers along winding paths and continuously upgrade them
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progress through increasingly difficult levels featuring trickier paths and tougher enemies
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explore the prestige skill tree: unlock permanent, game-changing abilities that make your defenses exponentially stronger
latest update
big demo update, now playable on Steam! v0.35 November 3, 2025
Hello everyone!
We just released an updated demo with new content and better balancing.
The demo is also available on Steam with 9 unlockable achievements.
https://store.steampowered.com/app/4101450/castle_idler_demo
List of updates:
- added more prestige upgrades
- added a 12th level
- added target prioritization for individual towers.
- added language support for Russian, Spanish, French, German, Portuguese, Chinese, and Japanese
- buffed the ice towers
If you have any feedback or suggestions, please share them with us in our discord! https://discord.gg/mHHQfjVSGj
view all updates
newest comments
awesome game
Fun little demo. Like another commenter said, ice towers are quite strong based on how the game is heavily balanced towards huge mobs of enemies. I personally think the blast radius upgrade might be a little strong. It increases radius a ton for cheap and with two upgrades, and ice tower is basically hitting every enemy it can.
Maybe if there was more variation in waves to mix in stronger enemies to incentivize using arrow towers a bit more.
Game doesn't load, tried on firefox, chrome and safari(mobile)
developer response: it seems like there's a connection issue with itch.io causing the game to not load. i'll see if there's another way to upload the game without using itch's embed upload
It's a fun little game, and I agree that the killstreak concept makes it stand out. The graphics are simple, but they work well and are cohesive with the UI. The upgrades are fun and unique for the most part, and they actually feel good and meaningful to get. It seems like it'll be a small, fast-paced game for the TD genre, and that's alright. Throw a little more content and depth in there for the full release, and I wouldn't mind paying a few $ for a few hours of this. It does need a little more to get to that point, but this is only a demo.
My only suggestion would be the upgrade menu for the towers. There's a lot of empty space in there, and though I'm sure there will be more tower types to fill it in the main game, they're a little annoying to click on. When I'm going fast and trying to fill in all the towers after prestiging, I often mouse out of the menu, which automatically closes it, and have to click again to reopen it. Making the upgrades inside larger or differently shaped to make them easier to accurately select, and/or only closing the upgrade menu after selecting an upgrade/clicking out/pressing esc, would be a huge QOL change imo, as it was the only thing I found frustrating. This may be personal preference though, so maybe a toggle?
Regardless, enjoyable demo. Thanks for sharing!
developer response: thank you for playing the demo and for your feedback!
Pros
++ Replacing waves with a killstreak feels very fresh for the tower defense genre.
+ The music is pleasant and fits well with the graphics, even if the enemies are simple recolours.
+ The prestige upgrades are well thought-out, not just "increase damage" or "enemies drop more gold".
So-Sos
~ The extra arrows upgrade only fires 1 arrow if it can only see 1 enemy when firing. It would be nice if all extra arrows were fired at the same enemy in that instance.
~ The split arrows prestige upgrade can bounce to enemies that are already dead (e.g. from an extra arrow from the same tower).
~ There's a weird visual bug with the price for population and arrow tower upgrades after prestiging. They're slightly offset to the left, rather than being in the centre. After being upgraded once, they jump to the centre, which is presumably where they should be from the start.
~ I don't really like the star mechanic, it feels like a plaster to make the game less of a slog to start with. I think if you started off with earning 1 gold for each enemy hit, you could get rid of it. I can understand keeping it though, because it gives the player something to do occasionally.
~ Seeing as there's a focus on record completion time, it would be nice to have a level select screen so you can retry levels easier.
Cons
- No targetting options. I get it's a very minimalist game, but it's still frustrating.
- If the tower menu button has a plot behind it, clicking on the menu button closes the tower menu and opens the above tower/plot menu. (e.g. In level 3, the bottom left plot and the plot just above it)
- The lack of any sort of boss is notable. It doesn't have to be a single large enemy, but it would be nice to have something for a bit more variety in gameplay.
- Only 2 tower types, which you can buy from the start. I was expecting to be able to unlock more tower types with prestige upgrades, so it was disappointing that wasn't the case.
Overall
For a minimalist TD incremental, the demo is a nice experience that you can finish fairly quickly. Looking at the Steam page, I can't see any evidence of content beyond the demo, so I'd be wary of looking to spend money on a full version until then. (Also the screenshots and gifs show wood instead of population, do they need to be updated?) Honestly, I'm a little concerned by the last key feature saying "(3 hours of playtime)". TDs in general are designed with much longer playtime than that and there is plenty here you could build on a lot more. I'd encourage you to re-think that "short experience" idea considering you're in the same space as The King is Watching, Plants vs. Zombies, Kingdom Rush...
developer response: Thanks for checking out the demo and for your feedback. I'm currently working on major updates for the official demo launch on Steam, and some of the points you brought up—like targeting options and new towers—have already been implemented. To get notified when the new demo is live, you can wishlist the game on Steam; you'll receive an automatic email notification as soon as it's available.
The full game will definitely feature more content beyond the current demo. I intend for it to be a short, fun experience, and I'm committed to pricing it fairly based on the final amount of content and reasonable playtime.
top comments
hint for absolute domination: spam ice tower.
i completed the full game in only 8 minutes.
Wow posted the exact second I refreshed. Played through on itch the other day and enjoyed it. Only thing i would say is that some of the skills felt a bit under-powered, while others felt way too good (arrow poison). Also the scaling cuts off the very top of the screen if you don't expand the game. Looking forward to the full release!
developer response: thanks for playing the demo and for your feedback.
It's a fun little game, and I agree that the killstreak concept makes it stand out. The graphics are simple, but they work well and are cohesive with the UI. The upgrades are fun and unique for the most part, and they actually feel good and meaningful to get. It seems like it'll be a small, fast-paced game for the TD genre, and that's alright. Throw a little more content and depth in there for the full release, and I wouldn't mind paying a few $ for a few hours of this. It does need a little more to get to that point, but this is only a demo.
My only suggestion would be the upgrade menu for the towers. There's a lot of empty space in there, and though I'm sure there will be more tower types to fill it in the main game, they're a little annoying to click on. When I'm going fast and trying to fill in all the towers after prestiging, I often mouse out of the menu, which automatically closes it, and have to click again to reopen it. Making the upgrades inside larger or differently shaped to make them easier to accurately select, and/or only closing the upgrade menu after selecting an upgrade/clicking out/pressing esc, would be a huge QOL change imo, as it was the only thing I found frustrating. This may be personal preference though, so maybe a toggle?
Regardless, enjoyable demo. Thanks for sharing!
developer response: thank you for playing the demo and for your feedback!
Pros
++ Replacing waves with a killstreak feels very fresh for the tower defense genre.
+ The music is pleasant and fits well with the graphics, even if the enemies are simple recolours.
+ The prestige upgrades are well thought-out, not just "increase damage" or "enemies drop more gold".
So-Sos
~ The extra arrows upgrade only fires 1 arrow if it can only see 1 enemy when firing. It would be nice if all extra arrows were fired at the same enemy in that instance.
~ The split arrows prestige upgrade can bounce to enemies that are already dead (e.g. from an extra arrow from the same tower).
~ There's a weird visual bug with the price for population and arrow tower upgrades after prestiging. They're slightly offset to the left, rather than being in the centre. After being upgraded once, they jump to the centre, which is presumably where they should be from the start.
~ I don't really like the star mechanic, it feels like a plaster to make the game less of a slog to start with. I think if you started off with earning 1 gold for each enemy hit, you could get rid of it. I can understand keeping it though, because it gives the player something to do occasionally.
~ Seeing as there's a focus on record completion time, it would be nice to have a level select screen so you can retry levels easier.
Cons
- No targetting options. I get it's a very minimalist game, but it's still frustrating.
- If the tower menu button has a plot behind it, clicking on the menu button closes the tower menu and opens the above tower/plot menu. (e.g. In level 3, the bottom left plot and the plot just above it)
- The lack of any sort of boss is notable. It doesn't have to be a single large enemy, but it would be nice to have something for a bit more variety in gameplay.
- Only 2 tower types, which you can buy from the start. I was expecting to be able to unlock more tower types with prestige upgrades, so it was disappointing that wasn't the case.
Overall
For a minimalist TD incremental, the demo is a nice experience that you can finish fairly quickly. Looking at the Steam page, I can't see any evidence of content beyond the demo, so I'd be wary of looking to spend money on a full version until then. (Also the screenshots and gifs show wood instead of population, do they need to be updated?) Honestly, I'm a little concerned by the last key feature saying "(3 hours of playtime)". TDs in general are designed with much longer playtime than that and there is plenty here you could build on a lot more. I'd encourage you to re-think that "short experience" idea considering you're in the same space as The King is Watching, Plants vs. Zombies, Kingdom Rush...
developer response: Thanks for checking out the demo and for your feedback. I'm currently working on major updates for the official demo launch on Steam, and some of the points you brought up—like targeting options and new towers—have already been implemented. To get notified when the new demo is live, you can wishlist the game on Steam; you'll receive an automatic email notification as soon as it's available.
The full game will definitely feature more content beyond the current demo. I intend for it to be a short, fun experience, and I'm committed to pricing it fairly based on the final amount of content and reasonable playtime.
Game doesn't load, tried on firefox, chrome and safari(mobile)
developer response: it seems like there's a connection issue with itch.io causing the game to not load. i'll see if there's another way to upload the game without using itch's embed upload