You have no engine, only a rope to a fixed anchor. Pump your swing, re-anchor to fling yourself across the field, and shatter the drifting rocks.
Your ship is tied to an anchor point by an elastic tether and cannot thrust freely. You build momentum by pumping the swing sideways, then drop a new anchor to slingshot your orbit somewhere new. Clear every rock to finish the wave; large rocks break into smaller, faster ones.
The rope swing is one of the oldest ideas in action games, from Pitfall! onward — momentum you cannot generate, only redirect.
This keeps only the rope. There is no engine and no ground; you pump a swing around a fixed anchor, release, and re-anchor mid-flight.
Removing the ground is what makes it original. In most swinging games the rope is a way to cross terrain; here it is the only way to move at all, so the game is about conserving momentum across a chain of anchors rather than about the leap between them.
Tether Drift puts a physics-driven swing-and-slingshot spin on the classic asteroid-shooting arcade genre, replacing free thrust with a single roped anchor. It is an original, free browser game made in-house for PlayPendium.