That's weird, no idea why that is. I tried replicating the issue on Opera and had no luck -sorry that happened! (space isn't connected to anything, enter starts it -but you'd have to be running the game to see that)
The shape of the key threw me off. It's shaped like a space bar, rather than any enter bar I've seen. It worked with Enter. With the weird screen look, it threw me off.
Game's a bit too far zoomed out for my tastes, but it's a pretty fun thing for what it is. Cheers.
