The spacebar is only used in the final level (level 11), so if you didn’t reach that point yet it might feel unclear. I’ll make that more readable earlier. About the sound, there are actually 5 different chirp variations that play randomly, but I agree it can still feel repetitive over time, so I’ll keep improving that. Glad you enjoyed the core puzzle design, even if it feels familiar—that was intentional to keep it easy to pick up.