This is the most fun shoot em up I've played.
Graphics as well as gameplay are top notch.
There are issues though as well:
-The 3 survival leaderboard achievements only seem to trigger randomly.
-The last campaign level at the very final stage causes immense lag which makes the game near to impossible to finish on pure difficulty.
-The loading times are pretty annoying when you play survival levels at pure difficulty. One mistake and you're out and you need to go through all the selection and loading stages again... why not just have a quick retry option?
-Playing with a retro filter on increases your score by 10%. I hate this. Why are you forcing me to make the game look ugly when I want to go for the highest possible scores?
You definitely should give it a try when you haven't picked it up yet and it pops up in future bundles again.