The best way to tell me about an issue you're having in Rebuild is to do it from inside the game's feedback menu, under the config menu (the gear icon). If the game's being especially glitchy you might still be able to get there by pressing the ESC key.
The feedback menu will send me an email with your recent logs and your most recent autosave, even if you do it from the main menu. Please try to be descriptive!
I try my best to recreate and fix every bug, but might not have time to respond to every report. If you need help with an issue, posting here on these forums is a better bet. We have a great little community here and people are happy to help.