This is the greatest game that Jeff Minter ever made. And hardly anyone realises this because they don't know how to play it, because they try to play it like some other game.
Let me tell you how to play Space Giraffe, and let that explain why this game is so good.
You need to relax, and pay attention to the game. Give it your full focus. What you do in this game is you don't shoot the basic enemies much, just enough to keep the power zone going, and then ram into the side of them as they reach the rim of the grid. That's the basic idea.
When you ram into enemies like this, it's called "bulling". Try to ram through as many as you can at once. It builds up your score, the multiplier, gives you extra lives... it's the main thing you want to try to do.
The power bar is the horizontal line that keeps coming towards you. You want to keep it away from you, otherwise you can't ram into enemies side-on and they kill you instead. The space between the power bar and you is called the power zone. You can also briefly make the power zone get big by collecting a "pod" power-up and jumping.
You can use the right stick of your joypad to aim your bullets through the power zone - just wiggle it a little and you'll probably hit a few enemies, enough to keep the power bar going. In later levels, you'll be specifically trying to aim for flowers, or spheres, or the other annoying enemies.
Now, this game throws a lot at you. So much that you can hardly see. But the thing is - that is what makes this game so amazing and different. This is a shooter that you don't play by shooting, and this is a game with visuals so intense that you need to play it by ear. Turn the volume up if you need to! Wear headphones if it helps!
Each enemy, each bullet, each power up, each collision has a different and distinct audio sound. Pay attention, listen to the game. Record the sound of each one in your brain.
Turn down the music and turn up the SFX if the music's getting in the way. You can't play this game without sound effects.
For levels where there's too much distortion on screen, you're going to feel your way through the level by sound. Listen for the announcement of each enemy, each bullet. You are endlessly auto-shooting, so you can hear when you've hit a flower, how far away it is, and when it "pings" off its stalk to come towards you.
The overall effect of playing this game with heightened sonic awareness, semi-blinded by the lights, racking up high scores, is that you end up with a feeling that is the nearest thing to "using the Force" you have ever, and possibly will ever feel. At least, that's how it is for me.
This is why this game is so good, so important. It is completely different, but it totally works. You just need to be receptive to the game and let it teach you how to play it, how to improve.
And good luck when you get to level 64. It's going to really mess your brain up and you're going to love it for that. :)