After struggling with both the theme and time due to my GCSE's happening in < 5 weeks I couldn't do my best, however this is what I ended up with by the end.

Controls: Arrow Keys to change dimensions, Space to change shape

Match both your shape and size with the endless stream of evil red boxes and triangles. Try to get the highest score you can!

Note: due to a memory leak the game will force close if left running for more than about 1 hour, after that time it was using over 3GB of memory on my system so YMMV.