The people giving this low scores are basically just pissed because they think the game is too hard. The fact is that the upgrade system does work, you just have to use your brains a little.
bugged.. if you crash on the top of the screen on the last boss you are stuck and cant move your spirit to another ship.. also plays very slow for me..
yeah its a bit short.. I got all 24 stars pretty fast.. Would be better if there was a shop and you could buy upgrades.. and maybe a mode where you are racing against others
best strategy is dont upgrade or spend money until you wipe. Then buy the best weapon you can afford. ($950 weapon) .. that one should last you until you have $1900 for last weapon and then you are done.. cakewalk
the flaw with this game is it doesn't tell you on the level map how many stars you got for that level.. which makes it hard to know what level to do for achievement.. so needs polishing
there are 2 solutions to level 16. I solved it a different way without the walkthrough. Just change under-left of yellow to blue and remove ball before it lands on it