iPhone GeoDefense Swarm Strategies
Usual Spoiler Warning
Medium Level 4 (The Long Way) - The bottom photo. Start with blasters and then replace them with missiles and lasers as you get more cash.
Medium Level 5 (Inward Spiral) - one of my favourite levels. It is easy once you work out the pattern. Upgrade from the centre out to maximise your score.
Medium Level 6 (Infiniconda) - I have come to quite like the thumper tower.
Medium Level 7
(Nucleotide) - This is quite a tough level.