It's uuuuuuuuuuuuuuh
Well I managed to hit 1950. The bit where three come at the same time is annoying to stop but I probably should've experimented with the controls more to see if there was a better way to fight them
The 3 at once will always be the same shape, so you don't need to get them all, you only need to protect the corresponding hole. I should have color coded the shapes so this would be a little more obvious, in the later stages it's so fast it's tricky to make out what shape they are.
I tried writing a game "director" that will adjust the game to your performance, however I ended up balancing it so that the difficulty ramps up very quickly... the actual gameplay isn't that interesting after a while, and half the point is losing, so I thought the harder the better.
My high score is 6350. Thanks for playing!