You are given a five digit calculator and told to make the number bigger. Digits are the constraint, not the number, so the early game is spent raising your base and adding digits before you can hold what you earn. Programs with .exe names bolt on new behaviour: one increments, one mines, one holds data through a reboot, one buys your upgrades for you.
Reboots are the reset layer and they cost you everything except what Data_Holder.exe was keeping. Past that there are research, quantum, singularity and infinity tabs waiting. It is dense, badly explained and rewarding once it clicks, and the several hundred version numbers in its title are honest about how long the author spent on it.