Excellent brain / algorithm game.
Under 10$, under 100 MB download.
Tip 1: Open up the included PDF manual and keep it open in a nearby window to have the commands handy.
Tip 2: Follow the data!
If you get stuck, most probably you output data from a node to an input through an instruction and omitted a "read" instruction on the opposite node to "receive" the input.
Tip 3: Remember that cycles flow through in sequence (one node after the other)