Cool stuff ! I'm not sure why the thief would need to be constantly visible, but it makes sense in terms of gameplay. I like a lot this kind of minimalist esthetic, it's both beautiful and highlight perfectly important gameplay features.
A few things that I think could be improved :
- doors look like they are vision zones, they have the exact same flat red look, which is okay once you know it, but it's not really clear
- I totally missed the indication that there was a dash at the start, so I found the beginning of the game really hard. I discovered its existence by doing random inputs when I got blocked at a point where it was impossible to pass without dashing
- I would add a bit of cooldown to the dash, and make the death take a bit more time, because currently it is necessary to spam it to pass most of the obstacles
Overall, that's a really cool game ! And congrats to the music composer, the soundtrack is pretty immersive !