It's nice to know that if our army's random desert base ever gets attacked by a bunch of massive bugs with no motive in mind, they will be conservative by putting no more than 10 soldiers to a wall and using incredibly underpowered weaponry.
Simple guide: Get multi-laser main weapon with missile wingmen. Buy the 3 kinds of Cash cards after the first level so you can afford max upgrades for you weapons right away. Then buy the More Purple card, the card that grants power-ups when tension bar reaches max, and maybe the card that makes every Special grant a time freeze. To get the 50x or 100x multiplier feats, just scrape as much as you can. It works especially well on bosses that shoot huge loads of bullets. Find a spot where you can stay in one spot, close to the bullet paths without getting hit.
Leveling up should happen faster. I don't like having to play through a single level 20 times before getting 2 points, and then still not being able to beat the boss.
Not everyone who hates the physics in this game sucks at it. I got the 99 bricks achievement pretty quickly, but I still hate the way the tower swings no matter how sturdy it should actually be.