Thunderground (C64)

Yes, another Atari 2600 port! This one came from a request by the owner of the Commodore 64 gaming news Facebook group and took 2-3 days mixed in with some Galaga work, and actual work. 

This game is sort of a cross between Combat and Dig-Dug. The goal on each level is to destroy the six pulsing nuclear bases on the surface of the planet. These are protected by two 'Core Ranger Tanks', which will try to ram and shoot at you.

As you move your vehicle you can dig a new tunnel if none exists, helping you reach your goal but also giving the enemy an easier route to you. The quicker you can destroy all of the bases, the bigger the bonus you will get for completing the level. Take too long and the white tank above the score will take one of your six lives!

Also hidden in the dirt on each level is a special token, collecting this will net you a bonus score and will vastly improve the scores earned for hitting bases on that round. 

White Tank - can only move in tunnels dug by you, or by the blue tank. 

Blue Tank - can dig its own tunnels to try and get to you faster

As the levels progress the speed of the enemy bullets,  the extent to which they will hunt you down, and the speed of the countdown timer, will all increase.