I played this on 150 fov for the true experience.
I really like the idea of the wall sliding thing, though it could use some polish. Especially because the camera noclips into the wall you're on. (this happens with any fov)
Also, some music would be great. When you destroy a portal, the silence is jarring.
But I like the timer after breaking a portal! Forces you to panic and to quickly progress in the level!
Good job, but could use polish.