Sandcastle Siege
Sandcastle Siege is a castle defense game that plays in the browser on phones, tablets and computers, for one player. It has a daily challenge, the same for everyone that day.
Grab crabs walking up the beach and fling them back into the sea before they wear down your sandcastle. The tide is the round timer and washes the beach clear, and between tides you buy repairs, gulls, pelicans and traps. After twenty tides the tide is endless, and the run ends when the castle falls.
How to play
- Press on a crab, drag toward the sea and let go to fling it
- Crabs that reach the castle wear it down. The tide ends the round
- Between tides, buy repairs and helpers
The game shows these steps as you play, the first time.
Controls
- Press on a crab, drag and let go to fling it
- The sea at the top takes it away
Tips
- Fling speed is read from the last 90 milliseconds of your drag and divided by the crab's weight, so a short fast flick beats a long slow pull.
- A crab flung fast enough bowls over any crab it hits on the way, so aim your throws through the thickest group rather than past it.
- The hermit's first trip to the water only knocks off its shell, and it walks back out stunned, so it needs two flings to be gone for good.
What do the helpers do?
A gull takes the crab nearest the castle every five, four or three seconds depending on how many gulls you own. A pelican scoops every crab near the leading one every nine seconds. Kelp slows crabs in a band up the beach, the moat slows them to 45% at the wall, and each bucket trap swallows three.
How does the wave bell work?
It costs 220 and fires by itself once a tide, the moment four crabs are close to the wall, washing every crab on the beach back into the sea. It resets at the next tide. The crab count per tide keeps growing and crabs walk 3.5% faster each tide, so it pays for itself late.
About this game
Made by Sucia in Houston, Texas. Built with AI assistance, designed and tested by Sucia. Last updated October 4, 2026. It plays in the browser on phones, tablets and computers, with no download and no sign-in; your best scores and progress stay in this browser on this device. Without a pass, every game is free for 5 minutes a game and 30 minutes a day; an Arcade pass removes the limit. How Sucia makes and tests its games.
Also by Sucia
Sucia Studio, a video editor for streamers, runs on Windows and Linux: record, cut long VODs by transcript and make Shorts. YouEdit, a video editing service for stream recordings, turns a recording into a YouTube video, Shorts, titles and the upload text, quoted in credits before it is made. Streaming on Twitch, Kick or YouTube? Sucia Live makes highlight videos and Shorts from your VOD.
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