To ensure old computers can't run it:
- Turn off any kind of culling and add a bunch of random objects out of view
- Overuse try/catch blocks (web developers will tell you this is good, it isn't)
- Use Vulkan or DirectX 12, if your engine supports them.
- If it's still running well, add some random loops somewhere that do nothing. Remember to turn off optimisation on your compiler, otherwise these will be optimised out.
- You could also use custom allocation and make it randomly set blocks of memory to garbage data to cause random crashes.
To give graphic designers/artists a heart attack:
- Use comic sans
- Use colours that buzz against each other
- Don't use anti-aliasing
- Draw your art in MS Paint to make sure it isn't transparent.