Good game, but I noticed two issues which made me loose my mind a little bit until I realised them.
ADD - takes variable inputs, but just fiddling around with the connections can give the false sense that any connection point can only have a single connection. At first I thought it added the input address to the output address, which would be inline with the INC/DEC commands, so it was weird when it seemed to just move the data.
RUN - this node has a “next instruction” connection which can be connected to with no sign of error, but doesn’t actually create a loop as one might initially expect, combined with me connecting IFZ to it made me confused about how IFZ works.