Sorry about the issues with the beam puzzles. I double checked the Level 5 puzzles for the latest patch and they should all be solveable, some of them seem a bit too confusing for a lot of players to figure out though. We'll work on telegraphing the correct path of the beam better in an upcoming patch. I haven't heard of the beam damaging the player the way you described but we'll check into that too.
Level 5 is the current end of the game so you didn't end up missing out on that much content. When we leave Early Access with Patch 3.0 Level 6 and the game endings will be added.