I've played some!  Platform + puzzle. Very nice! Very retro feeling too. ^_^

Cool, I have not played them all yet, but if I could make a suggestion, knowing how many keys I've collected would be nice

Yeah, that was one of those features that I had planned but never got around to doing. Maybe in the next version.

I want that feature too!  ^_^

Instant feedback as I play...

- First clicked on Help. I am not a native English speaker, so "move about" sounds funny, I am more used to "move around". Also the penultimate line seems truncated at "but that's". Mmm, the A of the title in the home page is truncated too, and the "tooltips" over the locked boxes at the bottom. Perhaps you use a font that I don't have, so the browser uses a default font not fitting in the given space. I am playing on latest Firefox.

- Wow, sprites are small! And moves are slow... That's OK. When I reach the flag, I instantly go to the main screen with next quest unlocked. I suggest to display a message in the game screen ("Goal reached" or similar), and asking to press a key to continue. It would make the transition less brutal.

I finished the level 5, which reminds me a bit of Lode Runner, a game I played a lot on my Apple //e...
Good job!