Kindle does not charge properly

If you use the charger that came with your kindle fire, you can rest knowing that it will not overcharge by leaving it plugged in too long. Usually 4 to 6 hours should fully charge it though.

It should take under 6 hours for a full charge.

The Kindle Fire HD, if completely discharged, may take several hours to begin to accept a charge again. Simply leave it plugged in long enough and the on-board system will sort it out.

try to reset the tablet.

Lithium ION batteries are usually rechargeable. The use mode for these batteries is that there are a set number of recharges that equate to the life of the battery. Usually that life is approximately 1,000 charges.
If you use your battery to 50% then recharge, you can do this ~2,000 times. As the life of the battery is used up, the maximum charge lessens which means where you may have had 8 hours of play time when the battery was new, you will only have 6 hours as the battery life is used up.
In order for a Lithium ION battery to recharge there must be at least a small amount of charge left as a "seed" for that recharge. If you drain a L-ION battery down to zero, it may never recharge again or the max charge will be reduced to an insignificant amount of the original full charge. eg instead of 8 hours you may only get 15 minutes, or 5 minutes, or no minutes.
You are much better off recharging when 50% depleted than using it up til your product stops.
L-ION batteries cannot be repaired only replaced. Most cheap products using L-ION batteries cannot have their batteries replaced.

Places like Batteries + are able to replace some tablet batteries.

You need to turn the unit on to see the model or serial number, we would try another charger letting it charge for a hour to see if it would accept a charge or turn on.

I’m happy to help further over the phone at https://www.6ya.com/expert/jonathan_828b54f422cbefdd

Dead Kindle I'm afraid.

Sounds like a rubbish app/game. Delete it.

If you like the game download it again and see if it behaves properly this time.

(apps/games are cheap/free for a reason.)

Good luck.

YOU NEED A NEW AC ADAPTER