For anyone wondering how the skill books stack with themselves, I've made a spreadsheet. ( https://docs.google.com/spreadsheets/d/1jI5k1wV1KOOaobF7g31uJBVQBEHfVZvSFG680SqYlPQ/edit?usp=sharing ) It shows how OP stacking multishot against 3 targets is, for example there is a 1% chance to hit 71 times with a single shot.
To everyone with issues with the game not running in the background.
This is a problem with Flash NOT specifically this game. To save computer resources Flashplayer will pause anytime it isn't visible on screen. To fix this issue follow these instructions from the anti-idle forum.
http://www.kongregate.com/forums/60-anti-idle-the-game/topics/198023-technical-issues-guide
Level 35 is impossible to get perfect score or best time on. The best you can do is 5 shots with 550 time bonus, or 6 shots with a 700 time bonus.
Also the wooden barriers need to break more consistently, several levels required you to hit perfectly in the center of a couple barriers to break them entirely. It becomes less of a puzzle and more pixel perfect aim.
I like how having 4 level 15 meteor guns with full damage upgrades just completely breaks the Ship DPS meter. Also the final boss was a bit anti-climatic especially since he dies instantly to a bomb, I assume that is not intentional since bombs don't work that well on any of the other bosses.