I've been playing this game off-and-on for some time now. Many hours. Finally, just recently, I'm able to fairly consistently get past the first level. I've even gotten past the second level a couple of times!

This game is so much harder than Isaac. That's not necessarily a bad thing, though!

Same here; doesn't help the dodge move is incredibly unreliable as the first few frames and the last several frames don't give any protection, but the forced movement can just as often get you nailed by another attack you couldn't position properly to dodge in the first place.

Yeah it does take time, but it's so worth it! In my opinion, anyway. :>

For those of you struggling with the game, I suggest keeping in mind 2 things:

1) Avoiding bullets is far more important and useful than dodge rolling. Not only are you locked into the movement once you start rolling, but there is a short cooldown and you may find yourself rolling into more danger. As opposed to simply side-stepping the original bullet and saving your roll for a more critical moment.

2) Use auto-aim with a controller. It might seem counter-productive, or cheap, or "easy", but trust me, this is how the pros who do no-hit runs do it. Get your controller, and allow the game to auto-aim for you. You can adjust the auto-aim settings to your liking, too.
By using auto-aim, you are free to focus more on avoiding bullets and positioning. Focus on your character and not the enemy or bullets - learn to rely on your peripheral vision and only make quick glances to enemies and oncoming attacks.

You might also want to make your priority unlocking NPCs at the beginning, and not worry too much about goals like beating the game, or unlocking shortcuts, etc.

Hope this helps some of you. Keep gunnin' and you'll be repeatedly beating the game in no time :D