I use Bedside Alarm Clock, got it off Amazon App store as one of the free apps of the day and it's pretty good but I can't remember how to make the screen dim... have you tried just dimming the screen in the stock clock app? It's still a little brighter than I would like it but it's better than nothing. The best alarm app I have ever used, in terms of reliability and features while still looking sleek and not having a lot of buttons, was the stock Motorola app. It would actually dim way further than you could manually dim tour screen and it had special wake up animations and stuff when you had it in the dock.
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