Hush Hush is a scare jumper. You run and something tries to scare you.
[h1]My game is running slowly?[/h1]
Since the game is graphicaly intensive running in full 1080p will depend on the power of your GPU, 1280x720 resolution will most likely work on any supported system.
[h1]Nope, still getting slide show.[/h1]
First reduce resolution. Then try reducing graphics quality in startup dialog. Then try disabling all graphics features in options. (You can leave smooth walls on as this setting only affects time in maze generation).
Game uses deffered rendering path and quite some post processing effects. Some of them are computationaly intensive and you will need proper graphics card to run with all settings on. Especially environment reflections (not screen space reflections) can be demanding for rendering.
If you still see slide show reduce graphics quality to 'fastest'. The game will look ugly but you might be able to play it.