TETHER
Free arcade game · plays in your browser · made with Sonnet 5.5
TETHER is an arcade game you can play free in your browser — no download, no account, nothing to install. If you came looking for Grapple, this is built in that mould. Sonnet 5.5 wrote the code; the prompt that produced it is on this page.
About TETHER
TETHER is a grapple-swing roguelite. You hook hanging lamps to swing through a long tunnel while a wall of darkness, the Dusk, eats the path behind you. Hold Space or the mouse button to hook the lamp ahead, let go to fly, and catch the next one before you fall into the void or the dark catches you. A run ends when your hearts run out, you fall, or the Dusk arrives, but every spark you collected is kept.
Between runs you spend sparks in the workshop. Eighteen upgrades in four branches improve your rope, your body, your gear and your luck, and unlock dash, glide and pulse. Waystations let you start a run in a zone you have already reached. Five zones, each with its own look and hazards (saws, falling rock, lava geysers, pistons, lasers, lightning, wind and flipped gravity), end in a gate where you choose one of several relics for the rest of the run. Reach 3,600 metres for the ending, then keep going in endless mode.
Controls: Space, W or the mouse button to hook; A and D to nudge; Shift to dash; S to glide; E to pulse; Esc to pause. It is built for a keyboard and mouse, not a phone. The score is your furthest distance in metres. Try swinging through the first zone without dashing at all: the dotted arc shows where letting go will send you.
How was TETHER made?
The prompt behind TETHER
"I want to create a game with you, so Sonnet 5.5 on high settings. I am giving you the full freedom to create any game that showcases your abilities and capabilities, how good you could create a game. The only thing that I like is the progression and the arc, that after each round your character could get improvements, and with those improvements you could go further." - Claude chose a grapple-swing roguelite. The build went: a render-free simulation (rope pendulum, five procedurally generated zones, hazards that telegraph, a chasing wall of darkness), a workshop of persistent upgrades with relics chosen at zone gates, a wordless intro and a spotlight tutorial, a renderer with parallax backdrops and a physical scarf, and synthesised sound. The economy and difficulty were tuned by a bot that plays every stage of the upgrade tree and a whole-career simulation, and a separate reviewer agent found six bugs that were then pinned with regression tests.
Categories and tags
Questions about TETHER
5
- Is TETHER free to play?
- Yes. TETHER is free, runs in your browser, and needs no account. Nothing to download, no plugin, no sign-up — open the page and play.
- Do I need to download or install TETHER?
- No. TETHER runs entirely in the browser on desktop. There is nothing to install and no launcher to sign in to.
- Which AI model made TETHER?
- TETHER was written by Sonnet 5.5, a model from Anthropic, using Claude Code. The prompt that produced it is published on this page, so you can see exactly what it was asked for.
- What is TETHER like?
- It is an arcade game, filed by its creator under Grapple and Swinging and Upgrades. TETHER is a grapple-swing roguelite.
- Does TETHER keep a high score?
- Yes. Any score TETHER reports goes to the leaderboard under the game, and you do not need an account for it to count.
Version 1.1 · updated 2026-09-30