Dryer not heating up - is it worth repairing? Possible DIY?

I have a Maytag gas-based dryer (Model # PYG2000AWW) from about 10-12 years ago that started getting much louder a few months ago. Then I started noticing that it needed 2 or 3 cycles just to dry a normal load of clothes. Now, the clothes will barely get even lukewarm despite 5+ cycles.

I’d rather not spend $600+ to replace the dryer if it means cheaply fixing it. Also, I am not sure if the excessively noisy tumbling is related to the heating process (or lack thereof).

I am a complete newbie at appliance repair, but I am willing to fiddle around with the D-I-Y route, and/or possibly professional repair (as long as the repair doesn’t cost as much as replacing the unit). Research online is sporadic; some say it might gas coils valves, some say it is the igniter, some say it is as basic as cleaning the ducts. Many others online say fixing a dryer is not too difficult.

For everyone’s reference, I took a very quick video of the noise this morning. Apologies in advance that the video is pretty dark (my basement is barely finished so lighting is limited). However, the : http://youtu.be/C9jlR0F7Ro8

1. Would you guys be able to tell me roughly what you think is wrong with the dryer? If I can at least have an idea as to what may be wrong, I can diagnose next action steps.

2. If possible, do you think it is an easy fix? Again, I am hoping to save money (especially if this is a quick and easy fix).

3. Do you think there are any safety issues with the dryer? Besides the video, I attached a photo of the dryer. The back grill (in the middle of the picture) seems a little darkened/burnt. I’m not sure what that means, though, if anything.

Any help or advice you guys can provide would be most appreciated!