DraStic

Just wondering if it's safe for the battery to charge while playing some games on this app. While in mid play I checked my bat and it was at 60%, then after a bit of time I decided to stop and just let it charge. I then checked it and it was at 58%. So, this has me a tad concerned as it's eating more power than it can gain.

It should be safe, but if your device uses more power than the charger can supply (for example, if you're charging the normal 2.5W limit over USB, which a lot of Android devices can easily surpass) then there's nothing you can really do to keep using it indefinitely. I know my JXD S7300 will still drain while charging if I'm using it heavily, there's nothing I can do but eventually stop using it and let it charge.

Lately after disabling the microphone and enabling Airplane mode, it slowly but definitely rises in battery while charging now.

you do run the risk of killing your battery early if you play by discahrging so be careful about doing this.