New puzzles, keyboard shortcuts, and more

Now that someone has actually completed all the original puzzles, I took some time to add a few more (difficult) puzzles. I'm still working up the courage to attempt them myself. See if you can beat me to it!

Additionally, this update brings keyboard shortcuts:

• Step: Ctrl+.
• Run/pause: Ctrl+Enter
• Stop/menu: Esc

Other improvements:

• More thorough testing of solutions (with random input)
• "Load" button merged into "Step" and "Run" (i.e. fewer button clicks required)
• Highlighting of next input and output

For the future, I'm hoping to add public leaderboards. I'm also considering adding character/string support to the language or maybe some sort of graphical output to add more variety to the puzzles (instead of just continuing to crank up the difficulty), although that might compromise one of my guiding principles for this game: prioritize difficulty over everything else, including fun ;)

Enjoy!