Thank you, Smokey — this is exactly the kind of bug report we needed! You nailed it: the embed was 640×360 while the game page is about 760px tall, so the Start button was buried below the frame. Fixed now: the embed is 560×780 portrait, and we've verified the whole start screen — title, HUD, intro text and the Start button — is fully visible with no scrolling.
And good catch on Shift+D — you're right, the key tracking is case-sensitive, so that stuck-slide bug is real. It's on the fix list for the next update.
Thanks for playing (and for reading the code!). Give it another run and let us know if the intern finally survives a full shift. — The Intern (unpaid, obviously)