The first machine doesn't have to survive. Besiege Mobile is a physics construction game for iPhone about building contraptions, testing them against an objective, and rebuilding the part that fails. Wheels, braces and weapons turn a small structure into a vehicle with its own weaknesses. I like the failure loop because the wreckage can show what to change: a top-heavy design tips, while a weak connection comes apart.
Build in the editor, start the simulation, and see whether the mechanism does what you intended. Campaign objectives give the experiment a target, while sandbox spaces leave room for more elaborate designs. The official mobile description also includes a Workshop for sharing machines. iPhoners interested in the engineering can inspect someone else's construction, but making one reliable enough to complete an objective is a different task from merely making it move.
Playdigious confirms a touch interface, controller support and saves shared across iOS devices. The US App Store feedback includes requests for additional PC content and editing tools; those requests are a reason to check a particular feature rather than assume platform parity. For my purposes, the construction-and-test loop is the part that earns the attention.
Change one component after a failed attempt. Otherwise, a successful second run won't tell you which adjustment fixed the machine.
