Yeah, that's a big one, and I intend to have a proper sophisticated keybind system (and potentially controller support) made for the full version. Technically there *is* a config file in AppData/Local/I_Wanna_Lockpick which has the key binds for certain (not all) buttons, but it uses numbers to represent which keyboard key is assigned to the bind. If you can find that file and open it up, see if you can't hack the binds. Go to the "[Controls]" section, and change around some numbers according to this list: http://www.davetech.co.uk/gamemakerkeyboardasciicodes . The ones you'll want to change are: Skip, which is actually an important toggle key that's normally bound to S, Jump (normally Shift), Undo (normally Z), Camera (normally C), and Action (normally X). There are unfortunately some hardcoded keybinds (E to toggle auto-run, and A which is a hold-button action after you get a certain item in the game), but I hope you can use this to make your experience slightly better.
I'd like to add my own vote for adding key rebinding sooner rather than later - while it's technically not unplayable, I have a tiny keyboard (60 total keys) and as things stand currently, accessing 'x' (for the master keys) and accessing the arrow keys cannot be done at the same time (to make up for the lack of space, I programmed my keyboard to have an arrow key mode that replaces that side of the keyboard - I could reprogram it, but this is literally the only time I've come up against a problem like this).
Even just adding wasd movement would fix this for me, but accessibility features like key rebinding is something best done sooner rather than later.
I understand the need for key rebinding, and I've been working on the options menu for a while now for the full release. Unfortunately, the demo version of the game was not maintained as its own version, and it would now be substantially harder for me to make a new demo version with key rebinds (harder than just continuing to work on the full game to completion). There *is* a config file in AppData/Local/I_Wanna_Lockpick which has some (but not all) key binds available to change by changing the ASCII values assigned to the buttons, but some binds in the demo (such as the 'A' and 'H' binds) are hardcoded. I'm aware it's not really ideal, but at the very least, it won't be an issue anymore in the full release.