Playing in expert difficulty. The basics are simple, you must destroy as many threats as you can. The more target you destroy and more your speed increase.
Just be careful with enemy projectiles. You can destroy any objects with a secondary weapons but you'll lose speed so you lose time to finish the level.
There is no end in this game.
You can grab the game here : http://www.asahi-net.or.jp/~cs8k-cyu/windows/tt_e.html
