Thanks Coa!
Yes, I think a RADAR is a great idea - I can to add that feature in along with a few other upgrades. Maybe the player can find the RADAR and a weapon upgrade etc. I had planned to do waves of enemies - where each wave will run slightly faster than the last....
A few game-play tips:
1- You can hear the direction and distance of the alien footsteps - but you have to stop the tank and listen closely to figure out where they are (I used 3D nodes for the audio), the footsteps will get louder and louder and pan left/right.
2- The aliens growl when they are very close to you. If they're right behind you, weave through the trees to slow them down and then quickly turn and shoot (you can also reverse in a straight line for this).
3- The "clicking" sound represents a new alien being spawned - they will always start far away (on the edge of the map) and run directly towards you in a straight line - so the center of the map is generally the safest place to rest, whilst the edges of the map may be the most dangerous.
4- If you stay in the center of the map, you can pivot the canon in a circle to pick-off the enemies whilst keeping a look-out for the Marines.
5- While doing this, try to keep the alien-count as low as possible so they can't attack you form multiple sides.
6- Whenever you spot a marine in the distance, drive to them, then quickly return to the center for safety.
7- Once you've collected all 5 Marines, you can then try to find the Temple (in the corner of the map, you can hide inside it.
8- The temple door will remain locked until you retrieve all the marines.
9- Stay inside the temple for a surprise (not finished yet).
