Diepix Arena 2 is an awesome fast paced shooter. Fight against 50 waves of enemies using a powerful tank that can be upgraded...UPGRADED? Say no more--I'll play it until I max everything!
You should really get bonuses for how high you get each time. Otherwise there is little incentive in getting as high as you can in comparison to going and killing all the monsters.
Best way to get the hard achievement is to set the options at Straight, Fixed, and Off. Then you want to collect the shapes in a circular motion. Got the achievement on my second try with those settings. Thumbs up so people can see this.