Games I played for many hours

Turing Complete (TC) (Steam link)

Game on Steam, guides you on how to build working computer (including writing assembly code for it) starting from NAND gates.

• Has best-in-class built-in tutorial, may take around ~20..40 hours to build your first architecture
• Currently guides you on building 3 different architectures: Overture, LEG and Sympony (in alpha-2.0 version)
• Hardware details are abstracted away, electrical current propagates to whole scheme at every tick
• Has nested components
• Has built-in assembly compiler (you create commands like «mov r0, r1» which auto-translate to for example 8-bit code like 01000001)
• Has sandbox mode

If you are new to CPU architecture, for sure choose this one.

Virtual Circuit Board (VCB) (Steam link)

Game on Steam, sandbox for simulating logic circuits (starting from logic gates).

• Has no built-in tutorial
• Clock synchronization need to be handled by user (electrical current propagation requires number of ticks depending of components used)
• Has virtual-memory system (you can load assembly programs into it)
• Has no nested components, but can fit much more stuff on the screen than TC
• There are some complaints on limited area to work on, but realistically you reach this limitation only on very big projects — by that point you probably outgrow gamified simulations already

I chose VCB over TC for my CPU builds because:

• It doesn’t guide you all the way (like TC), thus enhancing learning
• No nesting entails better “bird-view” on system you build
• It requires you to do gamified clock synchronization — a good balance between real life hardware problems and no synchronization requirement at all

Other games and software I heard about

Games:

• CRUMB — breadboard simulator, probably the best choice for going all the way deep to hardware level but still gamified
• Minecraft (redstone simulations) — this is probably where mass CPU-building hobby started
• Logic world — 3D game
• Silicon zeroes — focused more on architecture level rather than on low-level logic gates

Software popular among CPU hobbyists:

• Digital Logic Sim — works on same level as TC, but with more reliance on component nesting
• Logisim Evolution (Github link) — opensource software for simulating digital logic circuits starting from transistors/diods level. Very close to professional-level software.

Professional:

• Altium
• Protheus
• … many others …