Okay,
You are overtaxing your iPad Mini 3.
Any type of iPad hardware/software resource intensive games are going to tax your iPad Mini and cause it to heat up.
1.4 GBs of free data storage space is simply NOT enough.
An iDevice, ESPECIALLY AN iPad, needs to consistently maintain a MINIMUM of, at least 2-3 GBs of internal free data storage space for iOS to function and perform at an acceptable, nominal level and your iPad is well below that free storage space minimum.
This is one of the reasons Apple quietly did away with 16 GBs storage devices as after formatting and installation of iOS and having to keep a minimum of free data storage space, a 16 GBs iDevice ONLY has a usable, practical storage space of approx, between 9-10 GBs, or so.
Get rid of the RAM usage app as this maybe constantly always running in the background and eating up precious RAM AND CPU cycles and maybe responsible for additional heating up of your iPad.
Your model iPad ONLY has 1 GB of RAM. Not very much in this day and age when most iPad models now come with a minimum of 2 GBs of RAM, now.
Reduce the amount of active Website tabs, period!
Even though you are not viewing these additional website tabs, they are STILL active in the Web browser.
If you have some ridiculous number of active Website tabs open, cut this amount to, at least half.
10-20 tabs, or so, with that iPad model is acceptable, but if you have 50 or more active Website tabs open, then cut this amount in half! Period. No debate!
You need to free up free data storage space on an iPad/iDevice, you need to start by backing up your iPad to either Apple's iCloud or by connecting your iDevice to a computer running the latest iTunes or some other offsite, “cloud” data storage service, like Google Drive/Photos, DropBox, BOX, Flickr ( for images ), or other similar online, offsite, data storage/backup service.
Then delete any installed apps that you no longer use or use infrequently enough that they aren't missed ( you can always reinstalled any purchased or free apps at some time later, as you need them ).
Thin out/delete any music/videos/movies/TV shows/images/eBooks/eMagazine/iBooks/audiobooks/Documents/PDFs, etc.
If you use a POP email account on your iPad, delete/thin out any old saved emails that maybe saved to your iPad.
To permanently delete photos/images off of your iDevice go into the Photos app and find the Recently Deleted folder/album and permanently delete any photos/images stored in that folder/album.
Also, you can check to see what stuff is eating up all your valuable data storage space by going into the Settings
App,,General Settings Panel, in the right hand column, tap Storage & iCloud usage panel ( in iOS 11, it’s iPad Storage ), in the top Storage Panel, tap the Manage Storage panel, wait for a list of apps to generate that will tell you how much
space each app is taking up on your iDevice.
Then, do a hard reset of your iPad by holding down both the Home and sleep/wake buttons simultaneously until your
iPad goes to black and restarts with Apple logo, then release the buttons.
iDevices need to maintain, at the very least, a minimum of between 2-3 GBs of free data storage space, at all times, to
insure normal/nominal functionalities/operation and general overall performance of any iDevice.
Best of Luck to You!